CO: Individual County Chronologies

ADAMS created from ARAPAHOE. Act passed 15 April 1901; took effect 15 November 1902 following adoption of article XX of the Colorado Constitution in the November 1902 election. (Colo. Laws 1901, 13th sess., ch. 57, pp 133-137)

ADAMS lost to WASHINGTON and YUMA. (Colo. Laws 1903, 14th sess., chs. 81-82, pp. 169-176; Colo. Laws 1901, 13th sess., ch. 57, sec. 14/p. 137)

ADAMS lost to DENVER; 1st Airport Addition, 26th Ave. & Yosemite St. (City & County Map; Annexation Map)

ADAMS lost to DENVER; 2nd Airport Addition, 32nd Ave. & Havana St. (City & County Map; Annexation Map)

ADAMS lost to DENVER; Jett & Stillman, 52nd Ave. & Platte River. (Annexation Map)

ADAMS lost to DENVER; C.B. & Q. Industrial, Colorado Blvd. & 52nd St. (Annexation Map)

ADAMS lost to DENVER; 3rd Airport Addition, Havana St. & 26th Ave. (Annexation Map)

ADAMS lost to DENVER; 4th Airport Addition, Yosemite St. & Montview Blvd. (Annexation Map)

ADAMS lost to DENVER; 5th Airport Addition, Lima St. & 26th Ave. (Annexation Map)

ADAMS lost to DENVER; Airport Annexation. (Annexation Map)

ADAMS lost to DENVER; Union Pacific, Smith Rd. & Havana St. (Annexation Map)

ADAMS lost to DENVER; Marycrest, Federal Blvd. & W. 52nd Ave. (Annexation Map)

ADAMS lost to DENVER; Stapleton East, Havana St. & E. 56th Ave. (Annexation Map)

ADAMS lost to DENVER; Stapleton West, 56th Ave. & Quebec St. (Annexation Map)

ADAMS lost small area to DENVER; Associated Grocers, Valley Hwy. & 52nd Ave. (Annexation Map)

ADAMS lost to DENVER; Interstate, Havana St. & Interstate Hwy. 70. (Annexation Map)

ADAMS lost small area to DENVER; Union Pacific #2, Smith Road & Peoria St. (Annexation Map)

ADAMS lost to DENVER; Treatment Plant, Clifford Ave. between Lafayette St. & Downing St. (Annexation Map)

ADAMS lost to DENVER: Treatment Plant #2, Clifford Ave. (54th Ave.) between Downing St. & Ogden St. (Annexation Map)

ADAMS lost small area to DENVER; Marycrest #2, W. 54th & Columbine Road. (Annexation Map)

ADAMS lost to DENVER; Stapleton North, 56th Ave. & Yosemite St. (Annexation Map)

ADAMS lost to DENVER; Franklin-54th, Franklin St. & 54th Ave. (Annexation Map)

ADAMS lost to DENVER; North Franklin, 54th Ave. & Franklin St. (Annexation Map)

ADAMS lost to DENVER; Pump Station-56th Ave., 56th Ave. & Roslyn St. (Annexation Map)

ADAMS lost small area to DENVER; W. 52nd Ave. & Lincoln St. (Annexation Map)

ADAMS lost to DENVER. (USGS, 7.5 Minute Series, Sable Quadrangle, edition of 1965 [photorevised 1971] and edition of 1965 [photorevised 1979])

ADAMS lost to DENVER; Denver International Airport annexation. Referendum held 17 May 1988. (Dempsey, 142)

ADAMS lost to creation of BROOMFIELD. (Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274)

ALAMOSA created from CONEJOS and COSTILLA. (Colo. Laws 1913, 19th sess., ch. 6, pp. 19-24)

ARAPAHOE (Kansas Territory, extinct) created by Kansas Territory from non-county area; ARAPAHOE was located entirely within present Colorado. ARAPAHOE not fully organized, attached to MARSHALL (Kansas) "for all business purposes." (Kans. Terr. Laws 1855, 1st leg., chs. 37-38/pp. 217-218)

Kansas Territorial Governor, James Denver, issued commissions for county officials for ARAPAHOE (Kansas Territory, extinct). There is disagreement as to whether the county was ever officially organized. (Bancroft, 402; Fritz, 185-186; "Governor Denver's Admin.," 5:512; Kansas Counties, KSHS, http://www.kshs.org/genealogists/places/counties.htm, 2 March 2005; Wynkoop, 13:71-72)

ARAPAHOE (Kansas Territory, extinct) lost to creation of BRODERICK (Kansas Territory, extinct), EL PASO (Kansas Territory, extinct), FREMONT (Kansas Territory, extinct), MONTANA (Kansas Territory, extinct), and ORO (Kansas Territory, extinct). Act passed 7 February 1859, took effect 1 March 1859. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 1-5/pp. 357-358)

ARAPAHOE (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

ARAPAHOE created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 16/pp. 54-55)

DOUGLAS and WELD attached to ARAPAHOE "for judicial purposes." (Colo. Terr. Laws 1865, 4th sess., sec. 15/p. 53)

DOUGLAS and WELD fully organized, both detached from ARAPAHOE. (Colo. Terr. Laws 1866, 6th sess., pp. 60-61)

ARAPAHOE lost to creation of ADAMS and DENVER, and ARAPAHOE was renamed SOUTH ARAPAHOE. Act passed 15 April 1901; took effect 15 November 1902 following adoption of article XX of the Colorado Constitution in the November 1902 election. (Colo. Laws 1901, 13th sess., ch. 58, pp. 138-143)

SOUTH ARAPAHOE renamed ARAPAHOE. (Colo. Laws 1903, 14th sess., ch. 80, sec. 1/pp. 164-165)

ARAPAHOE lost to DENVER; Mountain View Park, Alameda Ave. & Federal Blvd. (City & County Map; Annexation Map)

ARAPAHOE lost to DENVER; University Hills #1, Yale Ave. & Colorado Blvd. (City & County Map; Annexation Map)

ARAPAHOE lost to DENVER; Davis Ranch, Jewell Ave. & Pecos St. (City & County Map; Annexation Map)

ARAPAHOE lost to DENVER; Kirkland #1, Yale Ave. & Steele St. (City & County Map; Annexation Map)

ARAPAHOE lost to DENVER: Mar Lee, Sheridan Blvd. and Mexico Ave.; University Hills #2, Yale Ave. & Dahlia St.; Brentwood, Federal Blvd. & Jewell St. (City & County Map; Annexation Map)

ARAPAHOE gained small area from DENVER by court order; Myrtle Hill Subdivision, part of sec. 31, Township 4 South, Range 67 West. (Arapahoe Co. Action #6556, Book 575, p. 229; City & County Map; Annexation Map)

ARAPAHOE lost to DENVER; Westwood, Federal Blvd. & Alameda Ave. (City & County Map; Annexation Map)

ARAPAHOE lost small area to DENVER; Kirkland #2, Yale Ave. & High St. (City & County Map; Annexation Map)

ARAPAHOE lost to DENVER; The Island, Federal Blvd. & Mississippi Ave. (City & County Map; Annexation Map)

ARAPAHOE lost small area to DENVER; Kimball Kroft-Block 2, Yale Ave. & Franklin St. (Annexation Map)

ARAPAHOE lost small area to DENVER; Correction No. 1, Colorado Blvd. & Dartmouth Ave. (Annexation Map)

ARAPAHOE lost to DENVER: Kimball Kroft-Block 1 2nd Filing, Yale Ave. & Humboldt St.; Sheridan Terrace, Sheridan Blvd. & Alameda Ave.; Kimball Kroft, Yale Ave. & Downing St. (Annexation Map)

ARAPAHOE lost small area to DENVER; Correction No. 2, Federal Blvd. & Kentucky Ave. (Annexation Map)

ARAPAHOE lost to DENVER: Wellshire Hills #1, Yale Ave. & Steele St.; Wellshire Golf Course, Colorado Blvd. & Hampden Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Fairhills, Federal Blvd. & Yale Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Sunset Terrace, Colorado Blvd. & C&S Tracts. (Annexation Map)

ARAPAHOE lost to DENVER: University Hills #3, Holly St. & Hampden Ave.; Monaco Gardens, Alameda Ave. & Monaco Blvd. (Annexation Map)

ARAPAHOE lost to DENVER; Wellshire Hills #2, Steele St. & Bates Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Wellshire Hills #3, Steele St. & Dartmouth Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Wellshire Hills #4, Steele St. & Bates Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Plaza Terrace #1, Mexico Ave. & Dahlia St. (Annexation Map)

ARAPAHOE lost to DENVER: Plaza Terrace #2, Mexico Ave. & Dahlia St.; Harvey Park, Jewell Ave. & Sheridan Blvd. (Annexation Map)

ARAPAHOE lost to DENVER: University Hills #4, Yale Ave. & Bellaire St.; University Hills #5, Colorado Blvd. & Amherst Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Virginia Village, Colorado Blvd. & Arizona Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Cherry Creek #1, Exposition Ave. & Cherry Creek. (Annexation Map)

ARAPAHOE lost to DENVER; Grace Methodist Church, Yale Ave. & Elm St. (Annexation Map)

ARAPAHOE lost to DENVER; Plaza Heights #1, Yale Ave. & Dahlia St. (Annexation Map)

ARAPAHOE lost to DENVER; Cherry Creek #2, Quebec St. & Cherry Creek. (Annexation Map)

ARAPAHOE lost to DENVER; Bear Creek, Sheridan Blvd. & Bear Creek. (Annexation Map)

ARAPAHOE lost to DENVER; Winston Downs, Alameda Ave. & Monaco St. (Annexation Map)

ARAPAHOE lost to DENVER; Cherry Creek #3, Roslyn St. & Cherry Creek. (Annexation Map)

ARAPAHOE lost to DENVER; Happy Canyon #1, Hampden Ave. & Holly St. (Annexation Map)

ARAPAHOE lost to DENVER: City Park Dairy, Dahlia St. & Cherry Creek; Hutchinsons University Place, Colorado Blvd. & Wesley Ave.; Panorama Park, Holly St. & Jewell Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Happy Canyon #2, Holly St. & Mansfield Ave. (Annexation Map; Denver Ord. 284-55, Engr. File 638, Engr. Plat Book 38/28)

ARAPAHOE gained 1.8 acres from DENVER by court ordered de-annexation: Kirkland 1st Addition, Cornell Ave. & University Blvd. (Annexation Map)

ARAPAHOE lost to DENVER; Plaza Heights #2, Vassar Ave. & Dahlia St. (Annexation Map)

ARAPAHOE lost to DENVER; Denver Public School No. 1, Virginia Ave. & Oneida St. (Annexation Map)

ARAPAHOE lost to DENVER; Hamilton Watch Co., Jewell Ave. & Kearney St. (Annexation Map)

ARAPAHOE lost to DENVER; Platte River, Yale Ave. & Platte River. (Annexation Map)

ARAPAHOE lost to DENVER: Wall School, Monaco St. Pkwy. & Virginia Ave.; Happy Canyon School, Mansfield Ave. & Holly St. (Annexation Map)

ARAPAHOE lost to DENVER; Loretto Heights College, Amherst Ave. & Federal Blvd. (Annexation Map)

ARAPAHOE lost to DENVER; St. Andrew Avellino Seminary, Birch St. & Mississippi Ave. (Annexation Map)

ARAPAHOE lost to DENVER: City Wolff, Jewell Ave. & Leyden St.; Ashgrove School, Mexico Ave. & Ivy St. (Annexation Map)

ARAPAHOE lost to DENVER: Glendale Area #1, Tennessee Ave. & Dahlia St.; Glendale Area #2, Kentucky Ave. & Dexter St. (Annexation Map)

ARAPAHOE lost 1.3 acres to DENVER; Glendale Area #3, Colorado Blvd. & Mississippi Ave. (Annexation Map; Denver Ord. 303-58, Engr. File 706, Engr. Plat Book 40/39)

ARAPAHOE lost to DENVER; Arapahoe County, Colorado Blvd. & Warren Ave. (Annexation Map; Denver Ord. 333-58, Engr. File 708, Engr. Plat Book 40/41)

ARAPAHOE lost to DENVER; Glendale Area #4, Kentucky Ave. & Dexter St. (Annexation Map)

ARAPAHOE lost to DENVER; Glendale Area #5, Exposition Ave. & Cherry Creek. (Annexation Map)

ARAPAHOE lost to DENVER; Glendale Area #6, Kentucky Ave. & Dexter St. (Annexation Map)

ARAPAHOE lost to DENVER; Hillel Academy, Hudson St. & Dakota Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Jones Annexation, Hudson St. & Dakota Ave. (Annexation Map)

ARAPAHOE lost small area to DENVER; Gibson St. & Blaine Ave. [not mapped]. (Annexation Map)

ARAPAHOE lost to DENVER: Bansbach Annexation, Hampden Ave. & Happy Canyon; Glendale Area #8, Tennessee Ave. & Birch St. (Annexation Map)

ARAPAHOE lost to DENVER; Garrett-Bromfield, Hampden Ave. & Holly St. (Annexation Map)

ARAPAHOE gained from DENVER by court ordered de-annexation: Hutchinson University Pl.; Colorado Blvd. & Wesley Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Evans Ave. Annexation, Jewell Ave. & Quebec St. (Annexation Map)

ARAPAHOE lost to DENVER: McMeen, Cherry Creek & Mississippi Ave.; Robinson Brick & Tile, Platte River Dr. & Yale Ave.; George Washington, Virginia Ave. & Kearney St. (Annexation Map)

ARAPAHOE lost to DENVER; Hutchinson University Pl., Colorado Blvd. & Wesley Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Fort Logan, Hampden Ave. & Lowell Blvd. (Annexation Map)

ARAPAHOE lost to DENVER: Oaksdale #1, Oneida St. & Jewell Ave.; Third Christian Reformed Church, Wesley Ave. & Ash St.; Prince of Peace, Colorado Blvd. & Wesley Ave. (Annexation Map)

ARAPAHOE lost to DENVER; College View, Federal Blvd. & Jewell Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Forest St., Leetsdale Dr. & Forest St. (Annexation Map)

ARAPAHOE lost to DENVER; Centennial Estates, Lowell Blvd. & Wagon Trail Dr. (Annexation Map)

ARAPAHOE lost to DENVER; Garrett-Bromfield #2, Hampden Ave. & Quebec St. (Annexation Map)

ARAPAHOE lost to DENVER; University Heights, Evans Ave. & Valley Hwy. (Annexation Map)

ARAPAHOE lost to DENVER; Deane Buick, Colorado Blvd. & Mississippi Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Oakesdale #3, Jewell Ave. & Oneida St. (Annexation Map)

ARAPAHOE lost to DENVER: Elm St., Leetsdale Dr. & Elm St.; Centennial Acres Trumac, Federal Blvd. & W. Union Ave.; Harris, Niagara St. & Panorama Lane. (Annexation Map)

ARAPAHOE lost to DENVER; East Mississippi, Quebec St. & Mississippi Ave. (Annexation Map)

ARAPAHOE lost to DENVER: Hampden North, Monaco St. Pkwy. & Hampden Ave.; Hampden South, Quebec St. & Hampden Ave. (Annexation Map)

ARAPAHOE lost small area to DENVER; Bruno, Colorado Blvd. & Arizona Ave. (Annexation Map)

ARAPAHOE lost to DENVER; East Belleview, Quincy Ave. & Syracuse St.; Eastern Star, Highline Canal & Wesley Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Range View #2, Fulton St. & Mississippi Ave. (Annexation Map)

ARAPAHOE lost small area to DENVER; Galilee Baptist Church, Parker Road & Mississippi Dr. (Annexation Map)

ARAPAHOE lost to DENVER; Range View #3, Mississippi Ave. & Havana St. (Annexation Map)

ARAPAHOE lost to DENVER; Lowry, 6th Ave. & Dayton St. (Annexation Map)

ARAPAHOE lost to DENVER; Hillcrest Reservoir, Happy Canyon Road & Monaco Blvd. (Annexation Map)

ARAPAHOE lost small areas to DENVER: Ames, Dahlia St. & C&S RR; Maddox, Vassar Ave. & Fairfax St. ; Rieger, Evans Ave. & Grape St. (Annexation Map)

ARAPAHOE lost to DENVER; Myrtle Hill, Colorado Blvd. & Amherst Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Bethesda, Iliff Ave. & Birch St. (Annexation Map)

ARAPAHOE lost to DENVER; Hallcraft, Hampden Ave. & Yosemite St. (Annexation Map)

ARAPAHOE lost small area to DENVER; Warren Ave., Warren Ave. & Grape St. (Annexation Map)

ARAPAHOE lost to DENVER: Dahlia-Iliff, S. Dahlia & E. Iliff Ave.; Ruby Hill, S. Pecos St. & W. Mexico Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Hampden Heights, Hampden Ave. & Yosemite St. (Annexation Map)

ARAPAHOE lost to DENVER; Golden Key, Yosemite St. & Syracuse Way. (Annexation Map)

ARAPAHOE lost to DENVER: Moore, Valley Hwy. & Yale Ave.; Dahlia-Evans, Dahlia St. & Evans Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Holly Ridge, Hampden Ave. & Monaco St. (Annexation Map)

ARAPAHOE lost small area to DENVER; Barnes, Colorado Blvd. & Arizona Ave. (Annexation Map)

ARAPAHOE gained from DENVER; Fort Logan, Hampden Ave. & Lowell Blvd., when the area was de-annexed by court order. ARAPAHOE lost to DENVER; Transfer Station, Cherry Creek & Jewell Ave. (extended) & Quebec St. (Annexation Map; "Elkins vs. Denver," in Pacific Reporter., 2d ser., vol. 402, 617-621)

ARAPAHOE gained from DENVER: Centennial Estates, Lowell Blvd. & Wagon Trail Dr., and Centennial Trumac, Federal Blvd. & Union Ave., when the earlier 11 September 1962 and 6 August 1963 annexations of these areas were dismissed by court order. (Annexation Map)

ARAPAHOE lost small area to DENVER; Moore #2, Vassar Ave. & Colo. State Hwy. 185. (Annexation Map)

ARAPAHOE lost to DENVER; Rutter, Evans Ave. & Elm St. (Annexation Map)

ARAPAHOE lost to DENVER; P.B.C., Sheridan Blvd. & Hampden Ave. (Annexation Map)

ARAPAHOE lost to DENVER: Federal-Dartmouth, Dartmouth Ave. & Federal Blvd.; Kennedy Golf Course, Hampden Ave. & Havana St.; Jeffersonian Apartments, Iliff Ave. & Valley Hwy. (Annexation Map)

ARAPAHOE lost to DENVER; Harris #2, Colorado Ave. & Oneida St. (Annexation Map)

ARAPAHOE lost to DENVER; State Hospital, W. Oxford Ave. & S. Lowell Blvd. (Annexation Map)

ARAPAHOE lost to DENVER; Holly Evans, Holly St. & Evans Ave. (Annexation Map)

ARAPAHOE lost to DENVER: Cherry Creek #4, Yale Ave. & S. Galena St.; General Motors, Warren Ave. & S. Dahlia St. (Annexation Map)

ARAPAHOE lost to DENVER: Teen City, Iliff Ave. & S. Parker Road; Cherry Creek Galleries #1, Cherry Creek Row & Jewell Ave. Ext. (Annexation Map)

ARAPAHOE gained small area from DENVER when .68 acres (1st Ave. & Dayton St.) were de-annexed by court order [too small to map]. (Annexation Map)

ARAPAHOE lost small area to DENVER; Glasier, Kentucky Ave. & Cherry Creek Row. (Annexation Map)

ARAPAHOE lost to DENVER; Belquince, Quincy Ave. & Valley Highway. (Annexation Map)

ARAPAHOE lost small area to DENVER; Golden Key Park, S. Syracuse Way & S. Xanthia St. (Annexation Map)

ARAPAHOE lost to DENVER; Decatur-Dartmouth, W. Dartmouth Ave. & S. Decatur St. (Annexation Map)

ARAPAHOE lost to DENVER; Glasier #2, Kentucky Ave. & Cherry Creek Row. (Annexation Map)

ARAPAHOE lost to DENVER; Floyd-Federal, W. Floyd Ave. & S. Federal Blvd. (Annexation Map)

ARAPAHOE lost to DENVER; Centennial Estates #2, W. Wagon Trail Dr. & S. Perry St. (Annexation Map)

ARAPAHOE lost to DENVER; Havana-Parker, S. Havana St. & Parker Road. (Annexation Map)

ARAPAHOE lost to DENVER; Conway, S Quebec St. & Jewell Ave. (Annexation Map)

ARAPAHOE lost small area to DENVER; Belquince #2, S. Monaco Pkwy. & Belleview Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Parker Road South, S. Parker Road & West of I-255. (Annexation Map)

ARAPAHOE lost small area to DENVER; Galilee Baptist Church #2, S. Rosemary Way & Mississippi Dr. (Annexation Map)

ARAPAHOE lost to DENVER; Dahlia-Iliff #2, S. Dahlia St. & Iliff Ave. (Annexation Map)

ARAPAHOE lost to DENVER; Parker Road South #2, S. Parker Road & West of I-225. (Annexation Map)

ARAPAHOE lost to DENVER: Valley Highway, Evans Ave. & Valley Highway; Marcor, Iliff Ave. & S. Dayton St. (Annexation Map)

ARAPAHOE lost to DENVER: Quebec-Quincy, Quincy Ave. & Quebec St.; Tech. Center #1, I-224 & S. Quebec St. (Annexation Map)

ARAPAHOE lost to DENVER; Tech. Center #2, Union Ave. & S. Quebec St. ARAPAHOE lost small area to DENVER, Harris Annex #3, Asbury Ave. & S. Oneida St. [too small to map]. (Annexation Map)

ARAPAHOE lost small area to DENVER; South Pontiac Way, Asbury Ave. & S. Pontiac Way. (Annexation Map)

ARAPAHOE lost to DENVER; Beverly Manor, W. Floyd Ave. & S. Federal Blvd. (Annexation Map)

ARAPAHOE lost to DENVER. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1971-2000)

ARAPAHOE lost small area to DENVER; Mississippi Ave. & S. Tamarac. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1980-1994)

ARCHULETA created from CONEJOS. (Colo. Laws 1885, 5th sess., pp. 40-42)

ARCHULETA exchanged with CONEJOS. (Colo. Laws 1905, 15th sess., ch. 74, pp. 153-154)

The extralegal Territory of Jefferson created ARRAPPAHOE (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 3, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; ARRAPPAHOE (Jefferson Territory) eliminated. (Smiley, 321-322)

BACA created from LAS ANIMAS. (Colo. Laws 1889, 7th sess., S.B. 37, pp. 26-28)

BEAVER (Utah) created by Utah Territory from IRON (Utah); included parts of present Colorado, Utah, and Nevada. (Utah Terr. Laws 1855, 5th sess., sec. 9/p. 7)

BEAVER (Utah) lost to HUMBOLDT (Utah Territory, extinct) and ST. MARY'S (Utah Territory, extinct); area within present Colorado was unchanged. (Utah Terr. Laws 1860, 10th sess./p. 19)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. BEAVER (Utah) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

BENT created by Colorado Territory from LAS ANIMAS and PUEBLO. (Colo. Terr. Laws 1870, 8th sess., sec. 3/pp. 16-17; sec. 2/p. 24)

BENT gained all of GREENWOOD (extinct); GREENWOOD eliminated. (Colo. Terr. Laws 1874, 10th sess., pp. 61-62)

BENT lost to creation of CHEYENNE and OTERO. (Colo. Laws 1889, 7th sess., S.B. 31, pp. 281-284 and S.B. 116, pp. 56-59)

BENT lost to creation of KIOWA, LINCOLN, and PROWERS. (Colo. Laws 1889, 7th sess., H.B. 337, pp. 222-225; S.B. 35, pp. 294-297; S.B. 106, pp. 234-237)

BEXAR (Texas) boundaries were implicitly expanded to cover all non-county area in the Republic of Texas when the boundaries of the Texas Republic were defined. BEXAR included territory in present Colorado, Kansas, New Mexico, Oklahoma, Texas, and Wyoming. Map depicts only that part of BEXAR in present Colorado. Changes in BEXAR boundaries between December 1836 and March 1848 did not affect the area within present Colorado and are not mapped. (Texas Repub. Laws 1836, 1st cong./p. 133)

The United States Congress admitted Texas to the Union; state of Texas continued to claim part of present Colorado. (U.S. Stat., vol. 9, res. 1[1846]/p. 108)

BEXAR (Texas) lost to creation of SANTA FE (Texas, extinct); BEXAR eliminated from present Colorado. (Texas Laws 1847, 2d reg. sess., ch. 87/p. 95)

BOULDER created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 22/p. 55)

BOULDER lost to creation of BROOMFIELD. (Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274)

BRODERICK (Kansas Territory, extinct) created by Kansas Territory from ARAPAHOE (Kansas Territory, extinct); BRODERICK was located entirely within present Colorado. Act passed 7 February 1859, took effect 1 March 1859. BRODERICK not fully organized. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 3, 8/pp. 358-359; Bancroft, 402)

BRODERICK (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

BROOMFIELD created from ADAMS, BOULDER, JEFFERSON, and WELD. (Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. All of present Colorado east of the Rocky Mountains became part of the District of Louisiana; the District was not fully organized and was attached to Indiana Territory for administrative and judicial purposes. CAPE GIRARDEAU District (Mo.) created by the District of Louisiana from non-county area; included parts of present Colorado, Kansas, and Missouri. (Terr. Papers U.S., 13: 51-52; U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283-289)

CAPE GIRARDEAU (Mo.) became a district (county) in Louisiana Territory when the District of Louisiana was renamed Louisiana Territory. (U.S. Stat., vol. 2, ch. 31[1805]/pp. 331-332)

CAPE GIRARDEAU District (Mo.) lost to NEW MADRID District (Mo.); area within present Colorado was unchanged. (Terr. Papers U.S., 13:541-542)

CAPE GIRARDEAU District (Mo.) gained from NEW MADRID District (Mo.), which was eliminated from present Colorado. (Ford, 5-6)

CAPE GIRARDEAU District (Mo.) eliminated from present Colorado when its boundaries were changed. (Royce, 676-677, pls. 112, 144; Terr. Papers U.S., 14:599-601)

CARBONATE (extinct) created from LAKE and small areas of SUMMIT; see 10 February 1879. (Colo. Laws 1879, 2d sess., pp. 45-47)

CARBONATE (extinct) was renamed LAKE and eliminated; LAKE in effect, regained all the territory it lost two days earlier. (Colo. Laws 1879, 2nd sess., p. 48)

CHAFFEE created from LAKE; CHAFFEE included all of LAKE that remained following the creation of CARBONATE (extinct) on 8 February 1879. CARBONATE was renamed LAKE on this date. (Colo. Laws 1879, 2d sess., p. 48)

The extralegal Territory of Jefferson created CHEYENNE (Jefferson Territory, extinct) in present Colorado, Wyoming, and a small area of Nebraska. (Jefferson Terr. Laws 1859, 1st sess., sec. 1, p. 190)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; CHEYENNE (Jefferson Territory) eliminated. (Smiley, 321-322)

CHEYENNE created from BENT and ELBERT. (Colo. Laws 1889, 7th sess., S.B. 116, pp. 56-59)

The Cheyenne Indian Reserve became a non-county area in Colorado Territory. (Colo. Terr. Laws 1861, 1st sess., pp. 53-57; Royce, 824-825, 838-839, pl. cxvi)

The Cheyenne Indian Reserve lost to PUEBLO. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

The Cheyenne Indian Reserve lost to EL PASO, and lost to creation of GREENWOOD (extinct). (Colo. Terr. Laws 1870, 8th sess., secs. 1, 5/pp. 16-17)

The Cheyenne Indian Reserve lost to creation of ELBERT; Cheyenne Indian Reserve eliminated as a non-county area in Colorado Territory. (Colo. Terr. Laws 1874, 10th sess., pp. 69-70)

CLEAR CREEK created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 26/p. 56)

GRAND not fully organized, attached to CLEAR CREEK "for legislative, legal and judicial purposes." (Colo. Terr. Laws 1874, 10th sess., sec. 4/p. 71)

GRAND fully organized, detached from CLEAR CREEK. (Black, 101-103)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. Boundaries were identical to the state of Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141; Noel, Mahoney, and Stevens, 14)

Colorado Territory created 17 counties from non-county area. All non-county area in Colorado Territory was eliminated except for the Cheyenne Indian Reserve. (Colo. Terr. Laws 1861, 1st sess., pp. 52-57)

GUADALOUPE (now CONEJOS) created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 4/pp. 52-53)

GUADALOUPE renamed CONEJOS. (Colo. Terr. Laws 1861, 1st sess., p. 143)

CONEJOS gained from COSTILLA. (Colo. Terr. Laws 1864, 3d sess., pp. 68-69)

CONEJOS attached to COSTILLA "for judicial purposes." (Colo. Terr. Laws 1865, 4th sess., sec. 18/p. 53)

CONEJOS was fully organized, detached from COSTILLA. (HRS Colo., Conejos, 41)

CONEJOS lost to creation of HINSDALE, LA PLATA, and RIO GRANDE. (Colo. Terr. Laws 1874, 10th sess., secs. 1-3, 10/pp. 66-68)

CONEJOS lost to creation of ARCHULETA. (Colo. Laws 1885, 5th sess., pp. 40-42)

CONEJOS exchanged with ARCHULETA. (Colo. Laws 1905, 15th sess., ch. 74, pp. 153-154)

CONEJOS lost to creation of ALAMOSA, gained small area from COSTILLA. (Colo. Laws 1913, 19th sess., ch. 6, pp. 19-24)

COSTILLA created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 2/p. 52)

COSTILLA lost to CONEJOS. (Colo. Terr. Laws 1864, 3d sess., pp. 68-69)

CONEJOS attached to COSTILLA "for judicial purposes." (Colo. Terr. Laws 1865, 4th sess., sec. 18/p. 53)

COSTILLA lost to creation of SAGUACHE; SAGUACHE not fully organized, attached to COSTILLA "for judicial purposes." (Colo. Terr. Laws 1866, 6th sess., p. 54)

Attachment of SAGUACHE to COSTILLA "for judicial purposes" was confirmed. (Colo. Terr. Laws 1866, 6th sess., sec. 8/p. 60)

SAGUACHE fully organized, detached from COSTILLA. (Hall, 4:304)

COSTILLA gained small area from LAS ANIMAS, lost small area to HUERFANO. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

CONEJOS was fully organized, detached from COSTILLA. (HRS Colo., Conejos, 41)

COSTILLA gained from SAGUACHE, lost to creation of RIO GRANDE. (Colo. Terr. Laws 1874, 10th sess., secs. 1, 13/pp. 66, 68)

COSTILLA lost to creation of ALAMOSA, and lost small area to CONEJOS. (Colo. Laws 1913, 19th sess., ch. 6, pp. 19-24)

CROWLEY created from OTERO. (Colo. Laws 1911, 18th sess., ch. 111, pp. 277-282)

CUSTER created from FREMONT and all of Non-County Area 2; Non-County Area 2 eliminated. (Colo. Laws 1876, 1st sess., ch. 21, par. 401-410/pp. 211-213)

DELTA created from GUNNISON. (Colo. Laws 1883, 4th sess., pp. 124-127)

City and County of DENVER created from SOUTH ARAPAHOE (now ARAPAHOE) following the approval of Colorado Constitutional Amendment XX by voters on 4 November 1902. The governor issued his official proclamation 1 December 1902. (Colo. Laws 1901, 13th sess., ch. 46, pp. 97-106 and ch. 68, pp. 162-165; King, 225-233; "Denver vs. Adams County," in Colo. Rpts., 33:1)

DENVER gained from ADAMS; 1st Airport Addition, 26th Ave. & Yosemite St. (City & County Map; Annexation Map)

DENVER gained from ADAMS; 2nd Airport Addition, 32nd Ave. & Havana St. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; Mountain View Park, Alameda Ave. & Federal Blvd. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; University Hills #1, Yale Ave. & Colorado Blvd. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; Davis Ranch, Jewell Ave. & Pecos St. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; Kirkland #1, Yale Ave. & Steele St. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE: Mar Lee, Sheridan Blvd. and Mexico Ave.; University Hills #2, Yale Ave. & Dahlia St.; Brentwood, Federal Blvd. & Jewell St. (City & County Map; Annexation Map)

DENVER lost small area to ARAPAHOE by court order: Myrtle Hill Subdivision, part of sec. 31, Township 4 South, Range 67 West. (Arapahoe Co. Action #6556, Book 575, p. 229; City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; Westwood, Federal Blvd. & Alameda Ave. (City & County Map; Annexation Map)

DENVER gained small area from ARAPAHOE; Kirkland #2, Yale Ave. & High St. (City & County Map; Annexation Map)

DENVER gained from ARAPAHOE; The Island, Federal Blvd. & Mississippi Ave. (City & County Map; Annexation Map)

DENVER gained from JEFFERSON; Inspiration Point, 48th Ave. & Sheridan Blvd. (Annexation Map)

DENVER gained small area from ARAPAHOE; Kimball Kroft-Block 2, Yale Ave. & Franklin St. (Annexation Map)

DENVER gained small area from ARAPAHOE; Correction No. 1, Colorado Blvd. & Dartmouth Ave. (Annexation Map)

DENVER gained from ADAMS [Jett & Stillman, 52nd Ave. & Platte River] and from ARAPAHOE [Kimball Kroft-Block 1 2nd Filing, Yale Ave. & Humboldt St.; Sheridan Terrace, Sheridan Blvd. & Alameda Ave.; Kimball Kroft, Yale Ave. & Downing St.]. (Annexation Map)

DENVER gained small area from ARAPAHOE; Correction No. 2, Federal Blvd. & Kentucky Ave. (Annexation Map)

DENVER gained from ADAMS; C.B. & Q. Industrial, Colorado Blvd. & 52nd St. (Annexation Map)

DENVER gained from ARAPAHOE: Wellshire Hills #1, Yale Ave. & Steele St.; Wellshire Golf Course, Colorado Blvd. & Hampden Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Fairhills, Federal Blvd. & Yale Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Sunset Terrace, Colorado Blvd. & C&S Tracts. (Annexation Map)

DENVER gained from ARAPAHOE: University Hills #3, Holly St. & Hampden Ave.; Monaco Gardens, Alameda Ave. & Monaco Blvd. (Annexation Map)

DENVER gained from ADAMS; 3rd Airport Addition, Havana St. & 26th Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Wellshire Hills #2, Steele St. & Bates Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Wellshire Hills #3, Steele St. & Dartmouth Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Wellshire Hills #4, Steele St. & Bates Ave. (Annexation Map)

DENVER gained from ADAMS; 4th Airport Addition, Yosemite St. & Montview Blvd. (Annexation Map)

DENVER gained from ADAMS [5th Airport Addition, Lima St. & 26th Ave.] and from ARAPAHOE [Plaza Terrace #1, Mexico Ave. & Dahlia St.]. (Annexation Map)

DENVER gained from ARAPAHOE: Plaza Terrace #2, Mexico Ave. & Dahlia St.; Harvey Park, Jewell Ave. & Sheridan Blvd. (Annexation Map)

DENVER gained from ARAPAHOE: University Hills #4, Yale Ave. & Bellaire St.; University Hills #5, Colorado Blvd. & Amherst Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Virginia Village, Colorado Blvd. & Arizona Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Cherry Creek #1, Exposition Ave. & Cherry Creek. (Annexation Map)

DENVER gained from ARAPAHOE; Grace Methodist Church, Yale Ave. & Elm St. (Annexation Map)

DENVER gained from ARAPAHOE; Plaza Heights #1, Yale Ave. & Dahlia St. (Annexation Map)

DENVER gained from ARAPAHOE; Cherry Creek #2, Quebec St. & Cherry Creek. (Annexation Map)

DENVER gained from ARAPAHOE; Bear Creek, Sheridan Blvd. & Bear Creek. (Annexation Map)

DENVER gained from ARAPAHOE; Winston Downs, Alameda Ave. & Monaco St. (Annexation Map)

DENVER gained from ARAPAHOE; Cherry Creek #3, Roslyn St. & Cherry Creek. (Annexation Map)

DENVER gained from ARAPAHOE; Happy Canyon #1, Hampden Ave. & Holly St. (Annexation Map)

DENVER gained from ARAPAHOE: City Park Dairy, Dahlia St. & Cherry Creek; Hutchinsons University Place, Colorado Blvd. & Wesley Ave.; Panorama Park, Holly St. & Jewell Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Happy Canyon #2, Holly St. & Mansfield Ave. (Annexation Map; Denver Ord. 284-55, Engr. File 638, Engr. Plat Book 38/28)

DENVER lost 1.8 acres to ARAPAHOE by court ordered de-annexation: Kirkland 1st Addition, Cornell Ave. & University Blvd. (Annexation Map)

DENVER gained from ARAPAHOE; Plaza Heights #2, Vassar Ave. & Dahlia St. (Annexation Map)

DENVER gained from ARAPAHOE; Denver Public School No. 1, Virginia Ave. & Oneida St. (Annexation Map)

DENVER gained from ARAPAHOE; Hamilton Watch Co., Jewell Ave. & Kearney St. (Annexation Map)

DENVER gained from ARAPAHOE; Platte River, Yale Ave. & Platte River. (Annexation Map)

DENVER gained from ARAPAHOE: Wall School, Monaco St. Pkwy. & Virginia Ave.; Happy Canyon School, Mansfield Ave. & Holly St. (Annexation Map)

DENVER gained from ARAPAHOE; Loretto Heights College, Amherst Ave. & Federal Blvd. (Annexation Map)

DENVER gained from ARAPAHOE; St. Andrew Avellino Seminary, Birch St. & Mississippi Ave. (Annexation Map)

DENVER gained from ARAPAHOE: City Wolff, Jewell Ave. & Leyden St.; Ashgrove School, Mexico Ave. & Ivy St. (Annexation Map)

DENVER gained from ARAPAHOE: Glendale Area No. 1, Tennessee Ave. & Dahlia St.; Glendale Area No. 2, Kentucky Ave. & Dexter St. (Annexation Map)

DENVER gained 1.3 acres from ARAPAHOE; Glendale Area No. 3, Colorado Blvd. & Mississippi Ave. (Annexation Map; Denver Ord. 303-58, Engr. File 706, Engr. Plat Book 40/39)

DENVER gained from ARAPAHOE; Arapahoe County, Colorado Blvd. & Warren Ave. (Annexation Map; Denver Ord. 333-58, Engr. File 708, Engr. Plat Book 40/41)

DENVER gained from ARAPAHOE; Glendale Area No. 4, Kentucky Ave. & Dexter St. (Annexation Map)

DENVER gained from ARAPAHOE; Glendale Area No. 5, Exposition Ave. & Cherry Creek. (Annexation Map)

DENVER gained from ARAPAHOE; Glendale Area No. 6, Kentucky Ave. & Dexter St. (Annexation Map)

DENVER gained from ARAPAHOE; Hillel Academy, Hudson St. & Dakota Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Jones Annexation, Hudson St. & Dakota Ave. (Annexation Map)

DENVER gained small area from ARAPAHOE; Gibson St. & Blaine Ave. [not mapped]. (Annexation Map)

DENVER gained from ARAPAHOE: Bansbach Annexation, Hampden Ave. & Happy Canyon; Glendale Area No. 8, Tennessee Ave. & Birch St. (Annexation Map)

DENVER gained from ARAPAHOE; Garrett-Bromfield, Hampden Ave. & Holly St. (Annexation Map)

DENVER gained from JEFFERSON; Bear Valley, Yale Ave. & Sheridan Blvd. (Annexation Map)

DENVER gained from ADAMS; Airport Annexation. (Annexation Map)

DENVER lost to ARAPAHOE by court ordered de-annexation: Hutchinson University Pl., Colorado Blvd. & Wesley Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Evans Ave. Annexation, Jewell Ave. & Quebec St. (Annexation Map)

DENVER gained from JEFFERSON; Green Meadows, Evans Ave. & Sheridan Blvd. (Annexation Map)

DENVER gained from ARAPAHOE: McMeen, Cherry Creek & Mississippi Ave.; Robinson Brick & Tile, Platte River Dr. & Yale Ave.; George Washington, Virginia Ave. & Kearney St. (Annexation Map)

DENVER gained from ADAMS; Union Pacific, Smith Rd. & Havana St. (Annexation Map)

DENVER gained from ARAPAHOE; Hutchinson University Pl., Colorado Blvd. & Wesley Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Fort Logan, Hampden Ave. & Lowell Blvd. (Annexation Map)

DENVER gained from ARAPAHOE: Oaksdale No. 1, Oneida St. & Jewell Ave.; Third Christian Reformed Church, Wesley Ave. & Ash St.; Prince of Peace, Colorado Blvd. & Wesley Ave. (Annexation Map)

DENVER gained from ARAPAHOE; College View, Federal Blvd. & Jewell Ave. (Annexation Map)

DENVER gained from JEFFERSON; West Jewell, Depew St. & Jewell Ave. (Annexation Map)

DENVER gained from JEFFERSON; West Bear Valley, Lamar St. & Yale Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Forest St., Leetsdale Dr. & Forest St. (Annexation Map)

DENVER gained from ARAPAHOE; Centennial Estates, Lowell Blvd. & Wagon Trail Dr. (Annexation Map)

DENVER gained from JEFFERSON; Inspiration Point Estates, Sheridan Blvd. & W. 52nd Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Garrett-Bromfield No. 2, Hampden Ave. & Quebec St. (Annexation Map)

DENVER gained from ARAPAHOE; University Heights, Evans Ave. & Valley Hwy. (Annexation Map)

DENVER gained from ARAPAHOE; Deane Buick, Colorado Blvd. & Mississippi Ave. (Annexation Map)

DENVER gained from ADAMS; Marycrest, Federal Blvd. & W. 52nd Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Oakesdale No. 3, Jewell Ave. & Oneida St. (Annexation Map)

DENVER gained from JEFFERSON; Bear Valley Church, Yale Ave. & S. Lamar St. (Annexation Map)

DENVER gained from JEFFERSON; Bear Valley South, Kenyon Ave. & S. Sheridan Blvd. (Annexation Map)

DENVER gained from ARAPAHOE: Elm St., Leetsdale Dr. & Elm St.; Centennial Acres Trumac, Federal Blvd. & W. Union Ave.; Harris, Niagara St. & Panorama Lane. (Annexation Map)

DENVER gained from ARAPAHOE; East Mississippi, Quebec St. & Mississippi Ave. (Annexation Map)

DENVER gained from ARAPAHOE: Hampden North, Monaco St. Pkwy. & Hampden Ave.; Hampden South, Quebec St. & Hampden Ave. (Annexation Map)

DENVER gained small area from ARAPAHOE; Bruno, Colorado Blvd. & Arizona Ave. (Annexation Map)

DENVER gained from ARAPAHOE: East Belleview, Quincy Ave. & Syracuse St.; Eastern Star, Highline Canal & Wesley Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Range View No. 2, Fulton St. & Mississippi Ave. (Annexation Map)

DENVER gained from ADAMS; Stapleton East, Havana St. & E. 56th Ave. (Annexation Map)

DENVER gained small area from ARAPAHOE; Galilee Baptist Church, Parker Road & Mississippi Dr. (Annexation Map)

DENVER gained from ARAPAHOE; Range View #3, Mississippi Ave. & Havana St. (Annexation Map)

DENVER gained from ARAPAHOE; Lowry, 6th Ave. & Dayton St. (Annexation Map)

DENVER gained from ARAPAHOE [Hillcrest Reservoir, Happy Canyon Road & Monaco Blvd.] and gained from JEFFERSON [Bear Valley South #2, Kenyon Ave. & Harlan St.; Bear Valley South #3, Kenyon Ave. & Sheridan Blvd.] (Annexation Map)

DENVER gained small areas from ARAPAHOE: Ames, Dahlia St. & C&S RR; Maddox, Vassar Ave. & Fairfax St. ; Rieger, Evans Ave. & Grape St. (Annexation Map)

DENVER gained from JEFFERSON: Runyan, Sheridan Blvd. & W. 10th Ave.; Crosby, Hampden Ave. & Lamar St. (Annexation Map)

DENVER gained from ARAPAHOE; Myrtle Hill, Colorado Blvd. & Amherst Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Bethesda, Iliff Ave. & Birch St. (Annexation Map)

DENVER gained from ADAMS; Stapleton West, 56th Ave. & Quebec St. (Annexation Map)

DENVER gained from ARAPAHOE; Hallcraft, Hampden Ave. & Yosemite St. (Annexation Map)

DENVER gained small area from ARAPAHOE; Warren Ave., Warren Ave. & Grape St. (Annexation Map)

DENVER gained from ADAMS [Associated Grocers, Valley Hwy. & 52nd Ave.] and gained from ARAPAHOE [Dahlia-Iliff, S. Dahlia & E. Iliff Ave.; Ruby Hill, S. Pecos St. & W. Mexico Ave.]. (Annexation Map)

DENVER gained from ARAPAHOE; Hampden Heights, Hampden Ave. & Yosemite St. (Annexation Map)

DENVER gained from ARAPAHOE; Golden Key, Yosemite St. & Syracuse Way. (Annexation Map)

DENVER gained from ARAPAHOE: Moore, Valley Hwy. & Yale Ave.; Dahlia-Evans, Dahlia St. & Evans Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Holly Ridge, Hampden Ave. & Monaco St. (Annexation Map)

DENVER gained small area from ARAPAHOE; Barnes, Colorado Blvd. & Arizona Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Transfer Station, Cherry Creek, Jewell Ave. (extended) & Quebec St. DENVER lost to ARAPAHOE; Fort Logan, Hampden Ave. & Lowell Blvd., when the area was de-annexed by court order. (Annexation Map; "Elkins vs. Denver," in Pacific Reporter., 2d ser., vol. 402, 617-621)

DENVER lost to ARAPAHOE: Centennial Estates, Lowell Blvd. & Wagon Trail Dr.; Centennial Trumac, Federal Blvd. & Union Ave., when the earlier 11 September 1962 and 6 August 1963 annexations of these areas were dismissed by court order. (Annexation Map)

DENVER gained small area from ARAPAHOE; Moore #2, Vassar Ave. & Colo. State Hwy. 185. (Annexation Map)

DENVER gained from ARAPAHOE; Rutter, Evans Ave. & Elm St. (Annexation Map)

DENVER gained from ADAMS; Interstate, Havana St. & Interstate Hwy. 70. (Annexation Map)

DENVER gained from ARAPAHOE; P.B.C., Sheridan Blvd. & Hampden Ave. (Annexation Map)

DENVER gained from ARAPAHOE: Federal-Dartmouth, Dartmouth Ave. & Federal Blvd.; Kennedy Golf Course, Hampden Ave. & Havana St.; Jeffersonian Apartments, Iliff Ave. & Valley Hwy. (Annexation Map)

DENVER gained from ADAMS [Union Pacific #2, Smith Road & Peoria St.] and gained from ARAPAHOE [Harris #2, Colorado Ave. & Oneida St.]. (Annexation Map)

DENVER gained from ARAPAHOE; State Hospital, W. Oxford Ave. & S. Lowell Blvd. (Annexation Map)

DENVER gained from ARAPAHOE; Holly Evans, Holly St. & Evans Ave. (Annexation Map)

DENVER gained from ADAMS [Treatment Plant, Clifford Ave. between Lafayette St. & Downing St.] and gained from JEFFERSON [Fehlmann, W. Yale Ave. & S. Wadsworth Blvd.]. (Annexation Map)

DENVER gained from ADAMS; Treatment Plant #2, Clifford Ave. (54th Ave.) between Downing St. & Ogden St. (Annexation Map)

DENVER lost to JEFFERSON; Bear Valley South #1, #2, #3, W. Kenyon Ave. & S. Sheridan Blvd., when the area was de-annexed by court order. (Annexation Map)

DENVER gained from JEFFERSON; Bear Valley Heights, W. Lehigh Ave. & S. Sheridan Blvd. (Annexation Map)

DENVER gained from ARAPAHOE: Cherry Creek #4, Yale Ave. & S. Galena St.; General Motors, Warren Ave. & S. Dahlia St. (Annexation Map)

DENVER gained from ARAPAHOE: Teen City, Iliff Ave. & S. Parker Road; Cherry Creek Galleries #1, Cherry Creek Row & Jewell Ave. Ext. (Annexation Map)

DENVER gained from JEFFERSON; Bear Valley Heights #2, W. Kenyon Ave. Ext. & S. Sheridan Blvd. (Annexation Map)

DENVER lost small area to ARAPAHOE when .68 acres (1st Ave. & Dayton St.) were de-annexed by court order [too small to map]. (Annexation Map)

DENVER gained small area from ARAPAHOE; Glasier, Kentucky Ave. & Cherry Creek Row. (Annexation Map)

DENVER gained from ARAPAHOE [Belquince, Quincy Ave. & Valley Highway] and gained from JEFFERSON [Bear Valley Park, W. Teller Ave. & Bear Creek]. (Annexation Map)

DENVER gained small area from ARAPAHOE; Golden Key Park, S. Syracuse Way & S. Xanthia St. (Annexation Map)

DENVER gained small area from ADAMS; Marycrest #2, W. 54th & Columbine Road. (Annexation Map)

DENVER gained from ARAPAHOE; Decatur-Dartmouth, W. Dartmouth Ave. & S. Decatur St. (Annexation Map)

DENVER gained from ARAPAHOE; Glasier #2, Kentucky Ave. & Cherry Creek Row. (Annexation Map)

DENVER gained from ARAPAHOE [Floyd-Federal, W. Floyd Ave. & S. Federal Blvd.] and gained from JEFFERSON [W. Inspiration Point, W. 52nd Ave. & Jay St. Ext.]. (Annexation Map)

DENVER gained from JEFFERSON; Sheridan-Kenyon; S. Sheridan Blvd. & W. Hampden Ave. (Annexation Map)

DENVER gained small area from JEFFERSON; Fehlman #2, W. Vassar Ave. & East of S. Wadsworth. (Annexation Map)

DENVER gained from JEFFERSON; Pinehurst, W. Quincy Ave. & S. Sheridan Blvd. (Annexation Map)

DENVER gained from ARAPAHOE; Centennial Estates #2, W. Wagon Trail Dr. & S. Perry St. (Annexation Map)

DENVER gained from ADAMS [Stapleton North, 56th Ave. & Yosemite St.] and gained from ARAPAHOE [Havana-Parker, S. Havana St. & Parker Road.]. (Annexation Map)

DENVER gained from JEFFERSON; Marston Lake #1, W. Quincy Ave. & Harlan St. (Annexation Map)

DENVER gained from ARAPAHOE; Conway, S Quebec St. & Jewell Ave. (Annexation Map)

DENVER gained from JEFFERSON; Marston Lake #2, W. Quincy Ave. & Wadsworth Blvd.-Sheridan Blvd. (Annexation Map)

DENVER gained small area from ARAPAHOE; Belquince #2, S. Monaco Pkwy. & Belleview Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Parker Road South, S. Parker Road & West of I-255. (Annexation Map)

DENVER gained small area from ARAPAHOE; Galilee Baptist Church #2, S. Rosemary Way & Mississippi Dr. (Annexation Map)

DENVER gained small area from JEFFERSON; Bear Valley Enclave, S. Lamar St. & W. Yale Ave. (Annexation Map)

DENVER gained small area from JEFFERSON; Bear Valley Heights Enclave, S. Harlan & W. Kenyon. (Annexation Map)

DENVER gained from ADAMS; Franklin-54th, Franklin St. & 54th Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Dahlia-Iliff #2, S. Dahlia St. & Iliff Ave. (Annexation Map)

DENVER gained from ARAPAHOE; Parker Road South #2, S. Parker Road & West of I-225. (Annexation Map)

DENVER gained from JEFFERSON; Cavalier Annexation, W. Hampden Ave. & S. Harlan. (Annexation Map)

DENVER gained from ARAPAHOE: Valley Highway, Evans Ave. & Valley Highway; Marcor, Iliff Ave. & S. Dayton St. (Annexation Map)

DENVER gained from ADAMS; North Franklin, 54th Ave. & Franklin St. (Annexation Map)

DENVER gained from ARAPAHOE: Quebec-Quincy, Quincy Ave. & Quebec St.; Tech. Center #1, I-224 & S. Quebec St. (Annexation Map)

DENVER gained from ARAPAHOE; Tech. Center #2, Union Ave. & S. Quebec St. DENVER gained small area from ARAPAHOE, Harris Annex #3, Asbury Ave. & S. Oneida St. [too small to map]. (Annexation Map)

DENVER lost to JEFFERSON when Cavalier Annex area (annexed to DENVER on 9 October 1971) was de-annexed from DENVER, but the entire area (with a small exception) was immediately re-annexed to DENVER [no mappable change]. (Annexation Map)

DENVER gained from ADAMS; Pump Station-56th Ave., 56th Ave. & Roslyn St. (Annexation Map)

DENVER gained small area from ARAPAHOE; South Pontiac Way, Asbury Ave. & S. Pontiac Way. (Annexation Map)

DENVER gained from JEFFERSON; West Marston, W. Quincy Ave. & S. Wadsworth. (Annexation Map)

DENVER gained from JEFFERSON; Vaughn, W. Hampden Ave. & S. Harlan St. (Annexation Map)

DENVER gained from ARAPAHOE; Beverly Manor, W. Floyd Ave. & S. Federal Blvd. (Annexation Map)

DENVER gained from JEFFERSON; Park West, W. Stanford Ave. & S. Kipling St. (Annexation Map)

DENVER gained small area from ADAMS; W. 52nd Ave. & Lincoln St. (Annexation Map)

DENVER gained from ADAMS. (USGS, 7.5 Minute Series, Sable Quadrangle, edition of 1965 [photorevised 1971] and edition of 1965 [photorevised 1979])

DENVER gained from ARAPAHOE and JEFFERSON. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1971-2000)

DENVER gained from ADAMS; Denver International Airport annexation. Referendum held 17 May 1988. (Dempsey, 142)

DENVER gained small area from ARAPAHOE [Mississippi Ave. & S. Tamarac] and gained from JEFFERSON [W. Grant Ranch Blvd. & S. Estes St.]. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1980-1994)

The state of Deseret was proposed by Mormon leaders, and the General Assembly met on 2 July 1849. The large state was to include parts of present Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming, but this proposal never gained widespread support in the U.S. Congress. Utah Territory, created on 9 September 1850, was not as extensive, but covered much of the area of the state of Deseret, including the Great Basin. Only the portion of Deseret in present Colorado is mapped here. (Atlas of Utah, 160-161; Brown, Cannon, and Jackson, 90-91)

The United States created Utah Territory from unorganized federal territory and part of the state of Texas; included all of present Colorado west of the Rocky Mountains. All that part of Deseret in present Colorado was included in Utah Territory. (U.S. Stat., vol. 9, ch. 51[1850]/pp. 453-458; Van Zandt, 159-160)

DOLORES created from OURAY. (Colo. Laws 1881, 3d sess., pp. 92-96)

DOLORES exchanged with SAN MIGUEL; mistake in description corrected 9 April 1927. (Colo. Laws 1923, 24th sess., ch. 90, pp. 245-246)

Boundary between DOLORES and SAN MIGUEL was redefined to correct mistake of 2 March 1923 [no change]. (Colo. Laws 1927, 26th sess., ch. 82, pp. 278-279)

In September 1970, DOLORES gained from MONTEZUMA by agreement of both county boards of commissioners. (Loretta Murphy, Montezuma Co. Mapping Dept., email, 26 November 2007)

DOUGLAS created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 14/p. 54)

DOUGLAS attached to ARAPAHOE "for judicial purposes." (Colo. Terr. Laws 1865, 4th sess., sec. 15/p. 53)

DOUGLAS fully organized, detached from ARAPAHOE. (Colo. Terr. Laws 1866, 6th sess., pp. 60-61)

DOUGLAS lost to creation of ELBERT. (Colo. Terr. Laws 1874, 10th sess., pp. 69-70)

EAGLE created from SUMMIT. (Colo. Laws 1883, 4th sess., pp. 127-130)

ELBERT created from DOUGLAS, GREENWOOD (extinct), and Cheyenne Indian Reserve. (Colo. Terr. Laws 1874, 10th sess., pp. 69-70)

ELBERT lost to creation of CHEYENNE. (Colo. Laws 1889, 7th sess., S.B. 116, pp. 56-59)

ELBERT lost to creation of KIT CARSON and LINCOLN. (Colo. Laws 1889, 7th sess. S.B. 48, pp. 225-228; S.B. 106, pp. 234-237)

EL PASO (Kansas Territory, extinct) created by Kansas Territory from ARAPAHOE (Kansas Territory, extinct); EL PASO was located entirely within present Colorado. Act passed 7 February 1859, took effect 1 March 1859. EL PASO not fully organized. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 5-6/p. 358; Bancroft, 402)

EL PASO (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

The extralegal Territory of Jefferson created EL PASO (Jefferson Territory, extinct) (Jefferson Terr. Laws 1859, 1st sess., sec. 4, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; EL PASO (Jefferson Territory) eliminated. (Smiley, 321-322)

EL PASO created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 12/p. 54)

EL PASO lost to FREMONT. (Colo. Terr. Laws 1866, 5th sess., pp. 47-48)

EL PASO gained from Cheyenne Indian Reserve. (Colo. Terr. Laws 1870, 8th sess., sec. 5/p. 17)

EL PASO lost to creation of TELLER. (Colo. Laws 1899, 12th sess., ch. 144, pp. 359-365)

The extralegal Territory of Jefferson created FOUNTAIN (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 5, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; FOUNTAIN (Jefferson Territory) eliminated. (Smiley, 321-322)

FREMONT (Kansas Territory, extinct) created by Kansas Territory from ARAPAHOE (Kansas Territory, extinct); FREMONT was located entirely within present Colorado. Act passed 7 February 1859, took effect 1 March 1859. FREMONT not fully organized. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 4, 9/pp. 358-359; Bancroft, 402)

FREMONT (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

FREMONT created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 10/pp. 53-54)

FREMONT gained from PUEBLO. (Colo. Terr. Laws 1864, 3d sess., pp. 69-70)

FREMONT gained from EL PASO and PUEBLO. (Colo. Terr. Laws 1866, 5th sess., pp. 47-48)

FREMONT lost to LAKE. (Colo. Terr. Laws 1867, 7th sess., ch. 20, sec. 45/p. 163)

FREMONT lost to HUERFANO and PUEBLO. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

FREMONT lost to creation of CUSTER. (Colo. Laws 1876, 1st sess., ch. 21, par. 401-410/pp. 211-213)

FREMONT lost to creation of TELLER. (Colo. Laws 1899, 12th sess., ch. 144, pp. 359-365)

GARFIELD created from SUMMIT. (Colo. Laws 1883, 4th sess., pp. 130-133)

GARFIELD lost to creation of RIO BLANCO. (Colo. Laws 1889, 7th sess., H.B. 107, pp. 325-328)

GARFIELD lost to ROUTT when the boundary was shifted to public land survey lines. (USGS, Glenwood Springs Quad., 1930)

ROUTT boundaries were clarified, placing its boundary with GARFIELD on public land survey lines. This act brought the Revised Statutes into compliance with the boundary lines that had long been observed [no change]. (Colo. Laws 1982, 53rd sess., ch. 127, pp. 480-481)

GILPIN created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 28/p. 56)

Boundary between GILPIN and JEFFERSON was clarified [no change]. (Colo. Laws 1913, 19th sess., ch. 86/p. 284)

GRAND created by Colorado Territory from SUMMIT; GRAND not fully organized, attached to CLEAR CREEK "for legislative, legal, and judicial purposes." GRAND's boundary with LARIMER (described as the "summit of the Snowy Range") was open to different interpretations and both counties claimed the area known as North Park [see also 1 November 1861]. In 1886, the Colorado Supreme Court ruled that the boundary ran on the Continental Divide, and the GRAND boundary is mapped here in accordance with that court ruling. (Colo. Terr. Laws 1874, 10th sess., pp. 70-71; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; Royce, 848-849, pl. cxvi)

GRAND fully organized, detached from CLEAR CREEK. (Black, 101-103)

GRAND lost to creation of ROUTT. The boundary between GRAND and ROUTT was open to different interpretations and is mapped here in accordance with a District Court decision of 21 July 1891. (Colo. Laws 1876, 1st sess., ch. 21, par. 393-400/pp. 209-211; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; "Routt County v. Grand County," in Pacific Reporter, 35: 1061-1064; Black, 113)

During the April 1886 term, the Colorado Supreme Court ruled on the boundary between GRAND and LARIMER. The decision, in favor of LARIMER, stated that the "snowy range," referenced in the 1861 law creating LARIMER, referred to the Continental Divide, not the Medicine Bow Mountains, located to the east. ("Grand County v. Larimer County," in Colo. Rpts., 9:268-281)

ROUTT boundaries were clarified, placing its boundary with GRAND on public land survey lines. This act brought the Revised Statutes into compliance with the boundary lines that had long been observed [no change]. (Colo. Laws 1982, 53rd sess., ch. 127, pp. 480-481)

GREAT SALT LAKE (now SALT LAKE, Utah) boundaries were redefined by Utah Territory. GREAT SALT LAKE gained from TOOELE (Utah) and non-county area; exchanged with UTAH (Utah); lost to DAVIS (Utah). GREAT SALT LAKE included parts of present Utah and Colorado. GREEN RIVER (Utah Territory, extinct) and islands in the Great Salt Lake south of WEBER (Utah) were attached to GREAT SALT LAKE "for election, revenue, and judicial purposes." (Utah Terr. Laws 1851, 1st sess., secs. 5-6/p. 163)

GREAT SALT LAKE (now SALT LAKE, Utah) lost to GREEN RIVER (Utah Territory, extinct) and lost to creation of SUMMIT (Utah); GREAT SALT LAKE eliminated from present Colorado. (Utah Terr. Laws 1853, 3d sess./pp. 14-15)

GREEN RIVER (Utah Territory, extinct) created by Utah Territory from non-county area; included parts of present Colorado, Utah, and Wyoming. GREEN RIVER not fully organized, attached to GREAT SALT LAKE (now SALT LAKE, Utah) "for election, revenue, and judicial purposes." (Utah Terr. Laws 1851, 1st sess., sec. 4/pp. 162-163)

GREEN RIVER (Utah Territory, extinct) gained from GREAT SALT LAKE (now SALT LAKE, Utah), SANPETE (Utah), and UTAH (Utah); lost to DAVIS (Utah) and lost to creation of SUMMIT (Utah). (Utah Terr. Laws 1853, 3d sess./pp. 14-15)

GREEN RIVER (Utah Territory, extinct) fully organized, detached from GREAT SALT LAKE (now SALT LAKE, Utah). (Gowans and Campbell, 63)

GREEN RIVER (Utah Territory, extinct) was disorganized and attached to GREAT SALT LAKE (now SALT LAKE, Utah) "for election, revenue and judicial purposes" because most settlers had left the area. (Utah Terr. Laws 1857, 7th sess./p. 1)

GREEN RIVER (Utah Territory, extinct) was reorganized, detached from GREAT SALT LAKE (now SALT LAKE, Utah). (Utah Terr. Laws 1858, 8th sess., ch. 11/pp. 19-20)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. GREEN RIVER (Utah Territory, extinct) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

GREENWOOD (extinct) created by Colorado Territory from PUEBLO, part of the Cheyenne Indian Reserve, and all of Non-County Area 1 (remnant of HUERFANO). (Colo. Terr. Laws 1870, 8th sess., sec. 1/p. 16)

GREENWOOD (extinct) lost to creation of ELBERT. (Colo. Terr. Laws 1874, 10th sess., pp. 69-70)

GREENWOOD (extinct) lost all territory to BENT; GREENWOOD eliminated. (Colo. Terr. Laws 1874, 10th sess., pp. 61-62)

GUNNISON created from LAKE; GUNNISON not fully organized, attached to LAKE "for senatorial, representative and judicial purposes." (Colo. Laws 1876, 1st sess., ch. 21, par. 411, 418/pp. 213-216)

GUNNISON fully organized, detached from LAKE. (Hall, 4:147)

GUNNISON lost to creation of PITKIN. (Colo. Laws 1881, 3d sess., pp. 89-92)

GUNNISON lost to creation of DELTA and MONTROSE. (Colo. Laws 1883, 4th sess., pp. 124-127, 136-139)

GUNNISON lost to creation of MESA. (Colo. Laws 1883, 4th sess., pp. 133-136)

GUNNISON lost to MONTROSE and lost to creation of UNCOMPAHGRE (extinct). (Colo. Laws 1883, 4th sess., pp. 139-142)

Legislature authorized PITKIN to gain from GUNNISON, dependent on local referendum; change did not take effect. (Colo. Laws 1907, 16th sess., ch. 143, pp. 317-318)

The extralegal Territory of Jefferson created HEELE (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 11, p. 192)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; HEELE (Jefferson Territory) eliminated. (Smiley, 321-322)

HINSDALE created from CONEJOS and LAKE. (Colo. Terr. Laws 1874, 10th sess., sec. 2/p. 66)

HINSDALE gained from LA PLATA, lost to creation of SAN JUAN. Act passed 31 January 1876; took effect 1 May 1876. (Colo. Terr. Laws 1876, 11th sess., secs. 1, 12/pp. 58, 61)

HINSDALE lost to creation of MINERAL. (Colo. Laws 1893, 9th sess., ch. 52, pp. 94-97; Colo. Laws 1895, 10th sess., ch. 92, pp. 205-206)

HUERFANO created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 6/p. 53)

HUERFANO lost to creation of LAS ANIMAS. (Colo. Terr. Laws 1866, 5th sess., pp. 49-50)

HUERFANO gained from COSTILLA and FREMONT, exchanged with LAS ANIMAS, lost to PUEBLO. A remnant of HUERFANO east of the Cheyenne Indian Reserve became Non-County Area 1; the former northwest corner of HUERFANO became Non-County Area 2. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

IRON (Utah) boundaries were redefined by Utah Territory. IRON gained non-county area, lost to creation of WASHINGTON (Utah); IRON included parts of present Utah, Colorado, and Nevada. WASHINGTON (Utah) not fully organized, attached to IRON "for election, revenue, and judicial purposes." (Utah Terr. Laws 1851, 1st sess., sec. 12/p. 164)

IRON (Utah) lost to creation of CARSON (Utah Territory, extinct); area within present Colorado was unchanged. (Utah Terr. Laws 1853, 3d sess./p. 19)

IRON (Utah) lost to creation of BEAVER (Utah), and lost to WASHINGTON (Utah) when its southern boundary was shifted slightly from 30 degrees, 30 minutes north latitude to four miles north of Fort Harmony. (Utah Terr. Laws 1855, 5th sess., secs. 9-10/p. 7)

WASHINGTON (Utah) fully organized, detached from IRON (Utah). (Larson, Andrew, 26)

IRON (Utah) lost to HUMBOLDT (Utah Territory, extinct) and ST. MARY'S (Utah Territory, extinct); area within present Colorado was unchanged. (Utah Terr. Laws 1860, 10th sess./p. 19)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. IRON (Utah) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

The extralegal Territory of Jefferson created JACKSON (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 10, p. 192)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; JACKSON (Jefferson Territory) eliminated. (Smiley, 321-322)

JACKSON created from LARIMER. (Colo. Laws 1909, 17th sess., ch. 179, pp. 432-436)

The extralegal Territory of Jefferson created JEFFERSON (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 9, p. 192)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; JEFFERSON (Jefferson Territory) eliminated. (Smiley, 321-322)

JEFFERSON created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 24/p. 56)

JEFFERSON boundaries were clarified [no change]. (Colo. Laws 1889, 7th sess., H.B. 256, pp. 100-101)

JEFFERSON lost to PARK. (Colo. Laws 1907, 16th sess., ch. 142, p. 316)

Boundary between JEFFERSON and GILPIN was clarified [no change]. (Colo. Laws 1913, 19th sess., ch. 86/p. 284)

JEFFERSON lost to DENVER; Inspiration Point, 48th Ave. & Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley, Yale Ave. & Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Green Meadows, Evans Ave. & Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; West Jewell, Depew St. & Jewell Ave. (Annexation Map)

JEFFERSON lost to DENVER; West Bear Valley, Lamar St. & Yale Ave. (Annexation Map)

JEFFERSON lost to DENVER; Inspiration Point Estates, Sheridan Blvd. & W. 52nd Ave. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley Church, Yale Ave. & S. Lamar St. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley South, Kenyon Ave. & S. Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley South #2, Kenyon Ave. & Harlan St. and Bear Valley South #3, Kenyon Ave. & Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Runyan, Sheridan Blvd. & W. 10th Ave. and Crosby, Hampden Ave. & Lamar St. (Annexation Map)

JEFFERSON lost to DENVER; Fehlmann, W. Yale Ave. & S. Wadsworth Blvd. (Annexation Map)

JEFFERSON gained from DENVER; Bear Valley South #1, #2, #3; W. Kenyon Ave. & S. Sheridan Blvd., when the area was de-annexed by court order. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley Heights, W. Lehigh Ave. & S. Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley Heights #2, W. Kenyon Ave. Ext. & S. Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Bear Valley Park, W. Teller Ave. & Bear Creek. (Annexation Map)

JEFFERSON lost to DENVER; W. Inspiration Point, W. 52nd Ave. & Jay St. Ext. (Annexation Map)

JEFFERSON lost to DENVER; Sheridan-Kenyon; S. Sheridan Blvd. & W. Hampden Ave. (Annexation Map)

JEFFERSON lost small area to DENVER; Fehlman #2, W. Vassar Ave. & East of S. Wadsworth. (Annexation Map)

JEFFERSON lost to DENVER; Pinehurst, W. Quincy Ave. & S. Sheridan Blvd. (Annexation Map)

JEFFERSON lost to DENVER; Marston Lake #1, W. Quincy Ave. & Harlan St. (Annexation Map)

JEFFERSON lost to DENVER; Marston Lake #2, W. Quincy Ave. & Wadsworth Blvd.-Sheridan Blvd. (Annexation Map)

JEFFERSON lost small area to DENVER; Bear Valley Enclave, S. Lamar St. & W. Yale Ave. (Annexation Map)

JEFFERSON lost small area to DENVER; Bear Valley Heights Enclave, S. Harlan & W. Kenyon. (Annexation Map)

JEFFERSON lost to DENVER; Cavalier Annexation, W. Hampden Ave. & S. Harlan. (Annexation Map)

JEFFERSON gained from DENVER when Cavalier Annex area (annexed to DENVER on 9 October 1971) was de-annexed from DENVER, but the entire area (with a small exception) was immediately re-annexed to DENVER [no mappable change]. (Annexation Map)

JEFFERSON lost to DENVER; West Marston, W. Quincy Ave. & S. Wadsworth. (Annexation Map)

JEFFERSON lost to DENVER; Vaughn, W. Hampden Ave. & S. Harlan St. (Annexation Map)

JEFFERSON lost to DENVER; Park West, W. Stanford Ave. & S. Kipling St. (Annexation Map)

JEFFERSON lost to DENVER. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1971-2000)

JEFFERSON lost to DENVER; W. Grant Ranch Blvd. & S. Estes St. (USGS, 7.5 Minute Series, various Colorado Quadrangles, 1980-1994)

JEFFERSON lost to creation of BROOMFIELD. (Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274)

Voters approved creation of the Territory of Jefferson and authorized formation of a provisional government. The first session of the Jefferson Territorial Legislature met 7 November 1859 in Denver City. This extralegal territory was not recognized by the United States. The Territory of Jefferson included all of present Colorado and parts of present Nebraska, Wyoming, and Utah. (Smiley, 305-318)

The extralegal Territory of Jefferson created 12 counties. Map depicts non-county area in the Territory of Jefferson. (Jefferson Terr. Laws 1859, 1st sess., pp. 190-192)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado. (Smiley, 321-322)

The United States created Kansas Territory from unorganized federal territory; included all of present Kansas and part of present Colorado. Map depicts that part of Kansas Territory in present Colorado. (Van Zandt, 138-139)

Non-county area in Kansas Territory lost to creation of ARAPAHOE (Kansas Territory, extinct) and WASHINGTON (Kansas). Map depicts non-county area of Kansas Territory in present Colorado. (Kans. Terr. Laws 1855, 1st leg., chs. 33, 37-38/pp. 214-218)

Non-county area in Kansas Territory gained from WASHINGTON (Kansas). Map depicts non-county area of Kansas Territory in present Colorado. (Kans. Terr. Laws 1857, 2d leg., sec. 33/p. 45)

Non-county area in Kansas Territory lost to creation of PEKETON (Kansas, extinct). Map depicts non-county area of Kansas Territory in present Colorado. (Kans. Terr. Laws 1860, ch. 42/p. 83 and ch. 78, sec. 4/p. 133)

Kansas Territory was eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

KIOWA created from BENT. (Colo. Laws 1889, 7th sess., H.B. 337, pp. 222-225)

KIT CARSON created from ELBERT. (Colo. Laws 1889, 7th sess. S.B. 48, pp. 225-228)

LAKE created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 32/p. 57; "Summit County v. Lake County," in Colo. Rpts., 70: 417-423)

LAKE gained from FREMONT. (Colo. Terr. Laws 1867, 7th sess., ch. 20, sec. 45/p. 163)

LAKE lost to SAGUACHE. (Colo. Terr. Laws 1872, 9th sess., pp. 81-82)

LAKE lost to creation of HINSDALE and LA PLATA. (Colo. Terr. Laws 1874, 10th sess., secs. 2-3, 10/pp. 66-68)

LAKE lost to creation of GUNNISON; GUNNISON not fully organized, attached to LAKE "for senatorial, representative and judicial purposes." (Colo. Laws 1876, 1st sess., ch. 21, par. 411, 418/pp. 213-216)

GUNNISON fully organized, detached from LAKE. (Hall, 4:147)

LAKE lost to creation of CARBONATE (extinct); see 10 February 1879. LAKE also lost small areas along the Continental Divide to SUMMIT. (Colo. Laws 1879, 2d sess., pp. 45-47)

CARBONATE was renamed LAKE; LAKE was renamed CHAFFEE. In effect, LAKE regained all the territory it lost two days earlier when CARBONATE (extinct) was created, and lost all of the territory that became CHAFFEE; CARBONATE eliminated. (Colo. Laws 1879, 2nd sess., p. 48)

LA PLATA created from CONEJOS and LAKE. (Colo. Terr. Laws 1874, 10th sess., sec. 3/p. 67)

LA PLATA lost to HINSDALE and lost to creation of SAN JUAN; act passed 31 January 1876; took effect 1 May 1876. (Colo. Terr. Laws 1876, 11th sess., secs. 1, 9, 12/pp. 58-61)

LA PLATA lost to creation of MONTEZUMA. (Colo. Laws 1889, 7th sess., H.B. 220, pp. 262-265)

LARIMER created by Colorado Territory from non-county area. LARIMER's western boundary (described as the "summit of the Snowy Range") was open to different interpretations. In 1886, the Colorado Supreme Court ruled that the boundary ran on the Continental Divide, and the LARIMER boundary is mapped here in accordance with that court ruling. (Colo. Terr. Laws 1861, 1st sess., sec. 20/p. 55; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281)

GRAND created by Colorado Territory from SUMMIT. GRAND's boundary with LARIMER (described as the "summit of the Snowy Range") was open to different interpretations and both counties claimed the area known as North Park. In 1886, the Colorado Supreme Court ruled that the boundary ran on the Continental Divide, and the LARIMER boundary is mapped in accordance with that court ruling. (Colo. Terr. Laws 1874, 10th sess., pp. 70-71; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; Royce, 848-849, pl. cxvi)

During the April 1886 term, the Colorado Supreme Court ruled on the boundary between GRAND and LARIMER. The decision, in favor of LARIMER, stated that the "snowy range," referenced in the 1861 law creating LARIMER, referred to the Continental Divide, not the Medicine Bow Mountains, located to the east. ("Grand County v. Larimer County," in Colo. Rpts., 9:268-281)

LARIMER lost to creation of JACKSON. (Colo. Laws 1909, 17th sess., ch. 179, pp. 432-436)

LAS ANIMAS created by Colorado Territory from HUERFANO. (Colo. Terr. Laws 1866, 5th sess., pp. 49-50)

LAS ANIMAS exchanged with HUERFANO, lost small area to COSTILLA. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

LAS ANIMAS lost to creation of BENT. (Colo. Terr. Laws 1870, 8th sess., sec. 3/pp. 16-17)

LAS ANIMAS lost to creation of BACA. (Colo. Laws 1889, 7th sess., S.B. 37, pp. 26-28)

LINCOLN created from ELBERT and BENT. (Colo. Laws 1889, 7th sess., S.B. 106, pp. 234-237)

LOGAN created from WELD. (Colo. Laws 1887, 6th sess., pp. 247-250)

LOGAN lost to creation of PHILLIPS. (Colo. Laws 1889, 7th sess., H.B. 127, pp. 288-292)

LOGAN lost to creation of SEDGWICK. (Colo. Laws 1889, 7th sess., H.B. 148, pp. 340-343)

MESA created from GUNNISON. (Colo. Laws 1883, 4th sess., pp. 133-136)

Spain claimed the territory west of the Louisiana Purchase as part of Mexico; included that part of present Colorado west of the Rocky Mountains. (Paullin, 64-66, plates 94-95)

The boundary of Spanish Mexico was altered when the Adams-Onis Treaty between the United States and Spain established the southern and western boundaries of the United States territory south of the parallel of 42 degrees north latitude. (Parry, 70:1-30; Van Zandt, 26-27)

Mexico gained its independence from Spain; that part of present Colorado that had been under the authority of Spain came under the control of the Republic of Mexico. ("Mexican War of Independence," New Handbook of Texas, 4:698)

Texas declared its independence from Mexico. The Republic of Texas claimed part of present Colorado that had been within the Mexican Republic [not mapped]. ("Republic of Texas," New Handbook of Texas, 5:537-538; Swindler, 9:247, 249)

The Republic of Mexico lost territory to the Republic of Texas when the boundaries of the Texas Republic were defined; Mexico lost part of present Colorado. ("Mexican War of Independence," New Handbook of Texas, 4:698; Texas Repub. Laws 1836, 1st cong./p. 133)

Treaty of Guadalupe Hidalgo ended the Mexican War between the United States and Mexico. Mexico recognized the United States' annexation of Texas and agreed that the Rio Grande River, not the Nueces River, was the true boundary between Mexico and Texas. ("Treaty of Guadalupe Hidalgo," New Handbook of Texas, 6:558-559; Parry, 102: 29-59; U.S. Stat., vol. 9[1848]/pp. 922-943)

MINERAL created from HINSDALE, RIO GRANDE, and SAGUACHE; mistake in description corrected 24 April 1895. (Colo. Laws 1893, 9th sess., ch. 52, pp. 94-97; Colo. Laws 1895, 10th sess., ch. 92, pp. 205-206)

MINERAL boundaries were clarified to correct mistake of 27 March 1893 [no change]. (Colo. Laws 1895, 10th sess., ch. 92, pp. 205-206)

All of present Colorado east of the Continental Divide became non-county area in Missouri Territory when Louisiana Territory was renamed Missouri Territory, and CAPE GIRARDEAU (Mo.), ST. LOUIS (Mo.), and STE. GENEVIEVE (Mo.) were eliminated from present Colorado. Map depicts non-county area of Missouri Territory in present Colorado. (Royce, 676-677, pls. 112, 144; Terr. Papers U.S., 14:599-601)

The boundary of Missouri Territory was altered when the Adams-Onis Treaty between the United States and Spain established the southern and western boundaries of the United States territory south of the parallel of 42 degrees north latitude. Map depicts non-county area of Missouri Territory in present Colorado. (Parry, 70:1-30; Van Zandt, 26-27)

Missouri Territory was eliminated upon creation of the state of Missouri. All that part of the former Territory north and west of the state of Missouri, including part of present Colorado, became unorganized federal territory. (U.S. Stat., vol. 3, ch. 22[1820]/pp. 545-548 and res. 1[1821]/p. 645; Van Zandt, 117)

MOFFAT created from ROUTT. (Colo. Laws 1911, 18th sess., ch. 173, pp. 516-521)

MONTANA (Kansas Territory, extinct) created by Kansas Territory from ARAPAHOE (Kansas Territory, extinct); MONTANA was located entirely within present Colorado. Act passed 7 February 1859, took effect 1 March 1859. MONTANA not fully organized. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 1, 7/pp. 357-359; Bancroft, 402)

MONTANA (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

MONTEZUMA created from LA PLATA. (Colo. Laws 1889, 7th sess., H.B. 220, pp. 262-265)

In September 1970, MONTEZUMA lost to DOLORES by agreement of both county boards of commissioners. (Loretta Murphy, Montezuma Co. Mapping Dept., email, 26 November 2007)

MONTROSE created from GUNNISON. (Colo. Laws 1883, 4th sess., pp. 136-139)

MONTROSE lost to creation of UNCOMPAHGRE (extinct) and gained from GUNNISON. (Colo. Laws 1883, 4th sess., pp. 139-142)

MONTROSE exchanged with OURAY when the boundary was placed on public land survey lines. (Colo. Laws 1913, 19th sess., ch. 46, pp. 140-141)

MORA (New Mexico) created by New Mexico Territory from TAOS (New Mexico); MORA included parts of present Colorado and New Mexico. (N.M. Terr. Laws 1859-1860, 9th assy. /p. 76)

The United States created Colorado Territory from New Mexico, Nebraska, and Utah Territories, and from the former Kansas Territory. MORA (New Mexico) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

MORGAN created from WELD. (Colo. Laws 1889, 7th sess., S.B. 40, pp. 267-270)

The extralegal Territory of Jefferson created MOUNTAIN (Jefferson Territory, extinct) in present Colorado and Utah. (Jefferson Terr. Laws 1859, 1st sess., sec. 12, p. 192)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; MOUNTAIN (Jefferson Territory) eliminated. (Smiley, 321-322)

The United States created Nebraska Territory from unorganized federal territory; included all of present Nebraska, and parts of present Colorado, North Dakota, South Dakota, Montana, and Wyoming. Map depicts that part of Nebraska Territory in present Colorado. (U.S. Stat., vol. 10, p. 277; Van Zandt, 136-137)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. Nebraska Territory was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. All of present Colorado east of the Rocky Mountains became part of the District of Louisiana; the District was not fully organized and was attached to Indiana Territory for administrative and judicial purposes. NEW MADRID District (Mo.) created by the District of Louisiana from non-county area; included all or part of seven states, including part of present Colorado. (Terr. Papers U.S., 13: 51-52; U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283-289)

NEW MADRID (Mo.) became a district (county) in Louisiana Territory when the District of Louisiana was renamed Louisiana Territory. (U.S. Stat., vol. 2, ch. 31[1805]/pp. 331-332)

NEW MADRID District (Mo.) gained from CAPE GIRARDEAU District (Mo.); area within present Colorado was unchanged. (Terr. Papers U.S., 13:541-542)

NEW MADRID District (Mo.) lost to CAPE GIRARDEAU District (Mo.); NEW MADRID eliminated from present Colorado. (Ford, 5-6)

The United States created New Mexico Territory from unorganized federal territory and land sold to the United States by the state of Texas; included part of present Colorado. Map depicts that part of New Mexico Territory in present Colorado. (U.S. Stat., vol. 9, ch. 49[1850]/pp. 446-452; Van Zandt, 160-162)

TAOS (New Mexico) created by New Mexico Territory from non-county area; TAOS included parts of present Colorado, Arizona, Nevada, and New Mexico. The non-county area in that part of Colorado included in New Mexico Territory was eliminated. (N.M. Terr. Laws 1851, 1st assy., 2d sess./p. 291)

Non-County Area 1 created from the remnant of HUERFANO east of the Cheyenne Indian Reserve. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

Non-County Area 1 (remnant of HUERFANO) lost all territory to creation of GREENWOOD (extinct); Non-County Area 1 eliminated. (Colo. Terr. Laws 1870, 8th sess., sec. 1/p. 16)

Non-County Area 2 created from the former northwest corner of HUERFANO. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

Non-County Area 2 lost all territory to creation of CUSTER; Non-County Area 2 eliminated. (Colo. Laws 1876, 1st sess., ch. 21, par. 401-410/pp. 211-213)

The extralegal Territory of Jefferson created NORTH (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 8, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; NORTH (Jefferson Territory) eliminated. (Smiley, 321-322)

ORO (Kansas Territory, extinct) created by Kansas Territory from ARAPAHOE (Kansas Territory, extinct); ORO was located entirely within present Colorado. Act passed 7 February 1859, took effect 1 March 1859. ORO not fully organized. (Kans. Terr. Laws 1859, 5th leg., ch. 44, secs. 2, 10/pp. 357-359; Bancroft, 402)

ORO (Kansas Territory) eliminated when the state of Kansas was admitted to the Union. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

OTERO created from BENT. (Colo. Laws 1889, 7th sess., S.B. 31, pp. 281-284)

OTERO lost to creation of CROWLEY. (Colo. Laws 1911, 18th sess., ch. 111, pp. 277-282)

OURAY created from SAN JUAN. (Colo. Laws 1876, 1st sess., ch. 21, par. 385-392/pp. 207-209)

OURAY lost to creation of DOLORES. (Colo. Laws 1881, 3d sess., pp. 92-96)

OURAY lost to creation of UNCOMPAHGRE (extinct); OURAY regained the lost portion when UNCOMPAHGRE (extinct) was renamed OURAY and eliminated three days later on 2 March 1883. (Colo. Laws 1883, 4th sess., pp. 139-142)

UNCOMPAHGRE (extinct) was renamed OURAY, and OURAY was renamed SAN MIGUEL; UNCOMPAHGRE eliminated. OURAY in effect regained the area it lost three days earlier to the creation of UNCOMPAHGRE and lost all the territory that became SAN MIGUEL. (Colo. Laws 1883, 4th sess., sec. 1/p. 123)

OURAY exchanged with MONTROSE when the boundary was placed on public land survey lines. (Colo. Laws 1913, 19th sess., ch. 46, pp. 140-141)

OURAY exchanged with SAN MIGUEL when part of the boundary was placed on public land survey lines. Mistake in description corrected 16 March 1984. (Colo. Laws 1917, 21st sess., ch. 38, pp. 118-119)

Boundary between OURAY and SAN MIGUEL was redefined to correct mistake of 17 April 1917 [no change]. (Colo. Laws 1984, 54th sess., ch. 230, pp. 816-817)

The extralegal Territory of Jefferson created PARK (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 6, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; PARK (Jefferson Territory) eliminated. (Smiley, 321-322)

PARK created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 30/pp. 56-57)

PARK gained from JEFFERSON. (Colo. Laws 1907, 16th sess., ch. 142, p. 316)

PEKETON (Kansas, extinct) created by Kansas Territory from non-county area. PEKETON included territory in present Colorado and Kansas. (Kans. Terr. Laws 1860, ch. 42/p. 83 and ch. 78, sec. 4/p. 133)

PEKETON (Kansas, extinct) lost territory when the state of Kansas was admitted to the Union; PEKETON eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

PHILLIPS created from LOGAN. (Colo. Laws 1889, 7th sess., H.B. 127, pp. 288-292)

PITKIN created from GUNNISON. (Colo. Laws 1881, 3d sess., pp. 89-92)

Legislature authorized PITKIN to gain from GUNNISON, dependent on local referendum; change did not take effect. (Colo. Laws 1907, 16th sess., ch. 143, pp. 317-318)

Legislature authorized creation of PLATTE (proposed) from WELD, subject to voter approval. Act repealed 9 February 1874; creation did not take effect. (Colo. Terr. Laws 1872, 9th sess., pp. 80-81; Colo. Terr. Laws 1874, 10th sess., p. 82)

Act of 9 February 1872, authorizing creation of PLATTE (proposed) from WELD, was repealed. (Colo. Terr. Laws 1874, 10th sess., p. 82)

PROWERS created from BENT. (Colo. Laws 1889, 7th sess., S.B. 35, pp. 294-297)

PUEBLO created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 8/p. 53)

PUEBLO lost to FREMONT. (Colo. Terr. Laws 1864, 3d sess., pp. 69-70)

PUEBLO lost to FREMONT. (Colo. Terr. Laws 1866, 5th sess., pp. 47-48)

PUEBLO gained from FREMONT, HUERFANO, and gained part of the Cheyenne Indian Reserve. (Colo. Terr. Laws 1867, 7th sess., ch. 20, p. 164)

PUEBLO lost to creation of BENT and GREENWOOD (extinct). (Colo. Terr. Laws 1870, 8th sess., sec. 3/pp. 16-17)

RIO BLANCO created from GARFIELD. (Colo. Laws 1889, 7th sess., H.B. 107, pp. 325-328)

RIO BLANCO lost to ROUTT when the boundary was shifted to public land survey lines. (USGS, Glenwood Springs Quad., 1930)

ROUTT boundaries were clarified, placing its boundary with RIO BLANCO on public land survey lines. This act brought the Revised Statutes into compliance with the boundary lines that had long been observed [no change]. (Colo. Laws 1982, 53d sess., ch. 127, pp. 480-481)

RIO GRANDE created from CONEJOS and COSTILLA. (Colo. Terr. Laws 1874, 10th sess., sec. 1/p. 66)

RIO GRANDE exchanged with SAGUACHE. (Colo. Laws 1879, 2d sess., p. 48)

RIO GRANDE lost to creation of MINERAL. (Colo. Laws 1893, 9th sess., ch. 52, pp. 94-97; Colo. Laws 1895, 10th sess., ch. 92, pp. 205-206)

ROUTT created from GRAND. The boundary between ROUTT and GRAND was open to different interpretations and is mapped here in accordance with a District Court decision of 21 July 1891. (Colo. Laws 1876, 1st sess., ch. 21, par. 393-400/pp. 209-211; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; "Routt County v. Grand County," in Pacific Reporter, 35: 1061-1064; Black, 113)

ROUTT lost to creation of MOFFAT. (Colo. Laws 1911, 18th sess., ch. 173, pp. 516-521)

ROUTT gained from GARFIELD and RIO BLANCO when the boundary was shifted to public land survey lines. (USGS, Glenwood Springs Quad., 1930)

ROUTT boundaries were clarified, placing its boundary with GARFIELD, GRAND, and RIO BLANCO on public land survey lines. This act brought the Revised Statutes into compliance with the boundary lines that had long been observed [no change]. (Colo. Laws 1982, 53d sess., ch. 127, pp. 480-481)

SAGUACHE created by Colorado Territory from COSTILLA; SAGUACHE not fully organized, attached to COSTILLA "for judicial purposes." (Colo. Terr. Laws 1866, 6th sess., p. 54)

Attachment of SAGUACHE to COSTILLA "for judicial purposes" was confirmed. (Colo. Terr. Laws 1866, 6th sess., sec. 8/p. 60)

SAGUACHE fully organized, detached from COSTILLA. (Hall, 4:304)

SAGUACHE gained from LAKE. (Colo. Terr. Laws 1872, 9th sess., pp. 81-82)

SAGUACHE lost to COSTILLA. (Colo. Terr. Laws 1874, 10th sess., sec. 13/p. 68)

SAGUACHE exchanged with RIO GRANDE. (Colo. Laws 1879, 2d sess., p. 48)

SAGUACHE lost to creation of MINERAL. (Colo. Laws 1893, 9th sess., ch. 52, pp. 94-97; Colo. Laws 1895, 10th sess., ch. 92, pp. 205-206)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. All of present Colorado east of the Rocky Mountains became part of the District of Louisiana; the District was not fully organized and was attached to Indiana Territory for administrative and judicial purposes. ST. LOUIS District (Mo.) created by the District of Louisiana from non-county area; included all or part of eight states, including part of present Colorado. (Terr. Papers U.S., 13: 51-52; U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283-289)

ST. LOUIS (Mo.) became a district (county) in Louisiana Territory when the District of Louisiana was renamed Louisiana Territory. (U.S. Stat., vol. 2, ch. 31[1805]/pp. 331-332)

ST. LOUIS District (Mo.) eliminated from present Colorado when its boundaries were changed. (Royce, 676-677, pls. 112, 144; Terr. Papers U.S., 14:599-601)

The extralegal Territory of Jefferson created ST. VRAIN (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 2, p. 190)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; ST. VRAIN (Jefferson Territory) eliminated. (Smiley, 321-322)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. All of present Colorado east of the Rocky Mountains became part of the District of Louisiana; the District was not fully organized and was attached to Indiana Territory for administrative and judicial purposes. STE. GENEVIEVE District (Mo.) created by the District of Louisiana from non-county area; included parts of present Colorado, Kansas, and Missouri. (Terr. Papers U.S., 13: 51-52; U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283-289)

STE. GENEVIEVE (Mo.) became a district (county) in Louisiana Territory when the District of Louisiana was renamed Louisiana Territory. (U.S. Stat., vol. 2, ch. 31[1805]/pp. 331-332)

STE. GENEVIEVE District (Mo.) eliminated from present Colorado when its boundaries were changed. (Royce, 676-677, pls. 112, 144; Terr. Papers U.S., 14:599-601)

SAN JUAN created by Colorado Territory from HINSDALE and LA PLATA. Act passed 31 January 1876; took effect 1 May 1876. (Colo. Terr. Laws 1876, 11th sess., secs. 1, 9, 12/pp. 58-61)

SAN JUAN lost to creation of OURAY. (Colo. Laws 1876, 1st sess., ch. 21, par. 385-392/pp. 207-209)

SAN MIGUEL created when OURAY was renamed SAN MIGUEL, and UNCOMPAHGRE (extinct) was renamed OURAY. (Colo. Laws 1883, 4th sess., sec. 1/p. 123)

SAN MIGUEL exchanged with OURAY when part of the boundary was placed on public land survey lines. Mistake in description corrected 16 March 1984. (Colo. Laws 1917, 21st sess., ch. 38, pp. 118-119)

SAN MIGUEL exchanged with DOLORES. Mistake in description corrected 9 April 1927. (Colo. Laws 1923, 24th sess., ch. 90, pp. 245-246)

Boundary between SAN MIGUEL and DOLORES was redefined to correct mistake of 2 March 1923 [no change]. (Colo. Laws 1927, 26th sess., ch. 82, pp. 278-279)

Boundary between SAN MIGUEL and OURAY was redefined to correct mistake of 17 April 1917 [no change]. (Colo. Laws 1984, 54th sess., ch. 230, pp. 816-817)

SANPETE (Utah) boundaries were redefined by Utah Territory. SANPETE gained non-county area, lost to MILLARD (Utah); SANPETE included parts of present Colorado and Utah. (Utah Terr. Laws 1851, 1st sess., sec. 11/p. 164)

SANPETE (Utah) lost to GREEN RIVER (Utah Territory, extinct). (Utah Terr. Laws 1853, 3d sess./pp. 14-15)

SANPETE (Utah) exchanged with JUAB (Utah); area within present Colorado was unchanged. (Utah Terr. Laws 1854, 4th sess., ch. 81/pp. 276-277)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. SANPETE (Utah) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

SANTA FE (Texas, extinct) created by the state of Texas from BEXAR (Texas). SANTA FE included territory in present Colorado, Kansas, New Mexico, Oklahoma, Texas, and Wyoming; only the portion in present Colorado is mapped here. SANTA FE boundaries changed on 31 December 1849, but the area within present Colorado was unchanged. (Texas Laws 1847, 2d reg. sess., ch. 87/p. 95)

Part of SANTA FE (Texas, extinct) in present Colorado was included in the area organized as Utah Territory on this date, although the purchase of the area by the United States was not officially approved until 13 December 1850. The remainder of SANTA FE was added to unorganized federal territory. SANTA FE effectively eliminated from present Colorado. (U.S. Stat., vol. 9, ch. 49[1850]/pp. 446-452 and ch. 51[1850]/pp. 453-458; Van Zandt, 159)

The extralegal Territory of Jefferson created SARATOGA (Jefferson Territory, extinct) in present Colorado. (Jefferson Terr. Laws 1859, 1st sess., sec. 7, p. 191)

Robert W. Steele, Provisional Governor of the Territory of Jefferson, declared the Territory disbanded upon the arrival of William Gilpin, the new territorial governor of Colorado; SARATOGA (Jefferson Territory) eliminated. (Smiley, 321-322)

SEDGWICK created from LOGAN. (Colo. Laws 1889, 7th sess., H.B. 148, pp. 340-343)

SUMMIT created by Colorado Territory from non-county area. SUMMIT's eastern boundary with LARIMER (described as the "summit of the Snowy Range") was open to different interpretations. In 1886, the Colorado Supreme Court ruled that the "snowy range" referred to the Continental Divide, and the SUMMIT boundary is mapped in accordance with that court ruling. (Colo. Terr. Laws 1861, 1st sess., secs. 20, 34/pp. 55, 57; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; "Summit County v. Lake County," in Colo. Rpts., 70: 417-423)

SUMMIT lost to creation of GRAND. (Colo. Terr. Laws 1874, 10th sess., pp. 70-71; "Grand County v. Larimer County," in Colo. Rpts., 9:268-281; Royce, 848-849, pl. cxvi)

SUMMIT gained small areas from LAKE, lost small areas to creation of CARBONATE (extinct) along the Continental Divide. (Colo. Laws 1879, 2d sess., pp. 45-47)

SUMMIT lost to creation of GARFIELD. (Colo. Laws 1883, 4th sess., pp. 130-133)

SUMMIT lost to creation of EAGLE. (Colo. Laws 1883, 4th sess., pp. 127-130)

TAOS (New Mexico) created by New Mexico Territory from non-county area; included parts of present Colorado, Arizona, Nevada, and New Mexico. (N.M. Terr. Laws 1851, 1st assy., 2d sess. /p. 291)

TAOS (New Mexico) lost to creation of MORA (New Mexico). (N.M. Terr. Laws 1859-1860, 9th assy. /p. 76)

TAOS (New Mexico) lost to creation of SAN JUAN (New Mexico Territory, original, extinct); area within present Colorado was unchanged. (N.M. Terr. Laws 1860-1861, 10th assy. /p. 16)

The United States created Colorado Territory from New Mexico, Nebraska, and Utah Territories, and from the former Kansas Territory. TAOS (New Mexico) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

TELLER created from EL PASO and FREMONT. (Colo. Laws 1899, 12th sess., ch. 144, pp. 359-365)

UNCOMPAHGRE (extinct) created from GUNNISON, MONTROSE, and OURAY; OURAY regained all of UNCOMPAHGRE when it was renamed OURAY and eliminated three days later on 2 March 1883. (Colo. Laws 1883, 4th sess., pp. 139-142)

UNCOMPAHGRE (extinct) was renamed OURAY; UNCOMPAHGRE eliminated. OURAY in effect regained the area it lost to the creation of UNCOMPAHGRE three days earlier. (Colo. Laws 1883, 4th sess., sec. 1/p. 123)

The state of Missouri was created from part of Missouri Territory; Missouri Territory was eliminated and all that part of the former Territory north and west of the state of Missouri, including part of present Colorado, became unorganized federal territory. (U.S. Stat., vol. 3, ch. 22[1820]/pp. 545-548 and res. 1[1821]/p. 645; Van Zandt, 117)

Unorganized federal territory gained part of SANTA FE (Texas, extinct) in present Colorado. Although the purchase of part of Texas by the United States was not officially approved until 13 December 1850, SANTA FE was effectively eliminated from present Colorado. (U.S. Stat., vol. 9, ch. 49[1850]/pp. 446-452 and ch. 51[1850]/pp. 453-458; Van Zandt, 159)

Unorganized federal territory lost to the creation of New Mexico Territory. New Mexico Territory included parts of present Colorado, Arizona, Nevada, and New Mexico. (U.S. Stat., vol. 9, ch. 49[1850]/pp. 446-452; Van Zandt, 160-162)

Unorganized federal territory in present Colorado lost all territory to creation of Kansas Territory and Nebraska Territory. (U.S. Stat., vol. 10, p. 277; Van Zandt, 136-137)

The area within the bounds of present Colorado that had been part of Kansas Territory temporarily reverted to unorganized federal territory until the official creation of Colorado Territory on 28 February 1861. (U.S. Stat., vol. 12, ch. 20 [1861]/pp. 126-128; Van Zandt, 138-139)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory (mapped here as unorganized federal territory). Unorganized federal territory was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

Treaty of Guadalupe Hidalgo ended the Mexican War between the United States and Mexico. Mexico recognized the United States' annexation of Texas and agreed that the Rio Grande River, not the Nueces River, was the true boundary between Mexico and Texas. That part of the former Republic of Mexico in present Colorado became unorganized federal territory. ("Treaty of Guadalupe Hidalgo," New Handbook of Texas, 6:558-559; Parry, 102: 29-59; U.S. Stat., vol. 9[1848]/pp. 922-943)

The unorganized federal territory in western Colorado became part of Utah Territory. (U.S. Stat., vol. 9, ch. 51[1850]/pp. 453-458; Van Zandt, 159-160)

UTAH (Utah) boundaries were redefined by Utah Territory. UTAH (Utah) gained non-county area, exchanged with GREAT SALT LAKE (now SALT LAKE, Utah); lost to JUAB (Utah) and SANPETE (Utah). UTAH included parts of present Utah and Colorado. (Utah Terr. Laws 1851, 1st sess., sec. 7/p. 163)

UTAH (Utah) lost to GREEN RIVER (Utah Territory, extinct); UTAH eliminated from present Colorado. (Utah Terr. Laws 1853, 3d sess./pp. 14-15)

The United States created Utah Territory from unorganized federal territory and part of the state of Texas; included all of present Colorado west of the Rocky Mountains. Map depicts that part of Utah Territory in present Colorado. (U.S. Stat., vol. 9, ch. 51[1850]/pp. 453-458; Van Zandt, 159-160)

Utah Territory created new counties and redefined the boundaries of other counties [GREAT SALT LAKE (now SALT LAKE, Utah), GREEN RIVER (Utah Territory, extinct), IRON (Utah), SANPETE (Utah), UTAH (Utah), and WASHINGTON (Utah)], eliminating all non-county area in that part of present Colorado included in Utah Territory. (Utah Terr. Laws 1851, 1st sess./pp. 162-164)

WASHINGTON (Utah) created by Utah Territory from non-county area; included parts of present Colorado, Nevada, and Utah. WASHINGTON not fully organized, attached to IRON (Utah) "for election, revenue, and judicial purposes." (Utah Terr. Laws 1851, 1st sess., sec. 13/p. 164)

WASHINGTON (Utah) gained from IRON (Utah) all along its northern line when the boundary was shifted slightly from 30 degrees, 30 minutes north latitude to four miles north of Fort Harmony. (Utah Terr. Laws 1855, 5th sess., sec. 10/p. 7)

WASHINGTON (Utah) fully organized, detached from IRON (Utah). (Larson, Andrew, 26)

WASHINGTON (Utah) lost to HUMBOLDT (Utah Territory, extinct) and ST. MARY'S (Utah Territory, extinct); area within present Colorado was unchanged. (Utah Terr. Laws 1860, 10th sess./p. 19)

The United States created Colorado Territory from Nebraska, New Mexico, and Utah Territories, and from the former Kansas Territory. WASHINGTON (Utah) lost to Colorado Territory and was eliminated from present Colorado. (U.S. Stat., vol. 12, ch. 59[1861]/pp. 172-177; Van Zandt, 141)

WASHINGTON (Kansas) created by Kansas Territory from non-county area; included parts of present Kansas and Colorado. WASHINGTON not fully organized, attached to ALLEN (Kansas) "for judicial and other purposes." (Kans. Terr. Laws 1855, 1st leg., ch. 33/pp. 214-215)

WASHINGTON (Kansas) lost to non-county area in Kansas Territory; WASHINGTON eliminated from present Colorado. (Kans. Terr. Laws 1857, 2d leg., sec. 33/p. 45)

WASHINGTON created from WELD. (Colo. Laws 1887, 6th sess., pp. 251-254)

WASHINGTON lost to creation of YUMA. (Colo. Laws 1889, 7th sess., H.B. 90, pp. 476-479)

WASHINGTON gained from ADAMS. (Colo. Laws 1903, 14th sess., ch. 81, pp. 169-172; Colo. Laws 1901, 13th sess., ch. 57, sec. 14/p. 137)

WELD created by Colorado Territory from non-county area. (Colo. Terr. Laws 1861, 1st sess., sec. 18/p. 55)

WELD attached to ARAPAHOE "for judicial purposes." (Colo. Terr. Laws 1865, 4th sess., sec. 15/p. 53)

WELD fully organized, detached from ARAPAHOE; LARIMER detached from BOULDER, attached to WELD "for judicial purposes." (Colo. Terr. Laws 1866, 6th sess., secs. 5-6/p. 60)

Legislature authorized creation of PLATTE (proposed) from WELD, subject to voter approval. Act repealed 9 February 1874; creation did not take effect. (Colo. Terr. Laws 1872, 9th sess., pp. 80-81; Colo. Terr. Laws 1874, 10th sess., p. 82)

Law of 9 February 1872, authorizing creation of PLATTE (proposed) from WELD was repealed. (Colo. Terr. Laws 1874, 10th sess., p. 82)

WELD lost to creation of WASHINGTON. (Colo. Laws 1887, 6th sess., pp. 251-254)

WELD lost to creation of LOGAN. (Colo. Laws 1887, 6th sess., pp. 247-250)

WELD lost to creation of MORGAN. (Colo. Laws 1889, 7th sess., S.B. 40, pp. 267-270)

WELD lost to creation of BROOMFIELD. (Colo. Laws 2001, 63d sess., ch. 103, pp. 256-274)

YUMA created from WASHINGTON. (Colo. Laws 1889, 7th sess., H.B. 90, pp. 476-479)

YUMA gained from ADAMS. (Colo. Laws 1903, 14th sess., ch. 82, pp. 173-176; Colo. Laws 1901, 13th sess., ch. 57, sec. 14/p. 137)

Colorado: Individual County Chronologies