MT: Individual County Chronologies

John H. Long, Editor; Peggy Tuck Sinko, Historical Compiler; Emily Kelley, Research Associate; Laura Rico-Beck, GIS Specialist and Digital Compiler; Peter Siczewicz, ArcIMS Interactive Map Designer; Robert Will, Cartographic Assistant

BEAVERHEAD created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 3/p. 675)

BEAVERHEAD became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145).

BEAVERHEAD re-created by Montana Territory; BEAVERHEAD gained from JEFFERSON and MADISON, lost to DEER LODGE. (Mont. Terr. Laws 1864, 1st leg., sec. 3/p. 529)

BEAVERHEAD lost to MADISON. (Mont. Terr. Laws 1867, 4th leg., sec. 2/pp. 102–103)

BEAVERHEAD lost to MADISON. (Mont. Terr. Laws 1868, 5th leg., p. 105)

BEAVERHEAD exchanged with DEER LODGE. (Mont. Terr. Laws 1871, 7th leg., ch. 20, secs. 2–3/pp. 429–430)

BEAVERHEAD authorized to gain part of the remnant of Dakota Territory that was transferred to Montana Territory on 17 February 1873. This act appears to have been based on faulty maps, since the area was actually surrounded by GALLATIN [no change]. (Mont. Terr. Laws 1874, 8th leg., p. 68; Van Zandt, 136, 145, 150; De Lacy, Map of the Territory of Montana)

BEAVERHEAD boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 732/p. 834)

BEAVERHEAD became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

BEAVERHEAD gained from MADISON. (Mont. Laws 1911, 12th leg., ch. 73/pp. 137–141)

BIG HORN created by petition and election from ROSEBUD and YELLOWSTONE. (Mont. Rev. Code 1921, sec. 4306/pp. 1556–1557; Burlingame, 17–18)

BLAINE created by petition and election from CHOUTEAU. (Mont. Rev. Code 1921, sec. 4307/pp. 1557–1559; Burlingame, 17–18)

BLAINE lost to creation of PHILLIPS. (Mont. Rev. Code 1921, sec. 4338/pp. 1599–1601; Burlingame, 17–19)

BROADWATER created from JEFFERSON and MEAGHER. Act passed 9 February 1897; took effect 1 March 1897. (Mont. Laws 1897, 5th leg., pp. 45–49)

BROADWATER lost to LEWIS AND CLARK. (Mont. Laws 1897, 5th leg., pp. 53–55)

BROADWATER gained from MEAGHER. (Mont. Laws 1911, 12th leg., ch. 25/pp. 36–38)

BROADWATER lost small area to GALLATIN when the boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 60/pp. 113–116)

CARBON created from PARK and YELLOWSTONE. Act passed 4 March 1895; took effect 1 May 1895. (Mont. Laws 1895, 4th leg., pp. 49–54)

CARBON lost to creation of STILLWATER. (Mont. Rev. Code 1921, sec. 4350/pp. 1612–1614; Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102; Burlingame, 17–18)

CARBON exchanged with YELLOWSTONE. (Mont. Laws 1919, 16th leg., chs. 75, 83/pp. 149–151, 157–158)

CARBON gained from YELLOWSTONE. (Mont. Laws 1925, 19th leg., ch. 30/pp. 34–35)

CARTER (Wyo., now SWEETWATER) created by Dakota Territory from LARAMIE (Wyo.); included a small area of present Montana. CARTER not fully organized, attached to LARAMIE "for representative and judicial purposes." (Dak. Terr. Laws 1867, 7th sess., ch. 7/pp. 122–123)

CARTER (Wyo., now SWEETWATER) lost small area in present Montana when Wyoming Territory boundaries were defined; CARTER eliminated from present Montana. (U.S. Stat., vol. 15, ch. 235 [1868], secs. 1, 17/pp. 178, 183; Van Zandt, 136, 144)

CARTER created from FALLON. (Mont. Laws 1917, 15th leg., ch. 56/pp. 71–76; "State ex rel. Ford v. Schofield," in Mont. Rpts., 53: 502–518)

Boundary between CARTER and POWDER RIVER clarified [no change]. (Mont. Laws 1929, 21st leg., ch. 45/pp. 75–76)

CASCADE created by Montana Territory from CHOTEAU (now CHOUTEAU), FERGUS, LEWIS AND CLARK, and MEAGHER; CASCADE not fully organized, attached to CHOTEAU "for judicial purposes." Act passed 12 September 1887; took effect 19 December 1887. (Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105–109)

CASCADE fully organized, detached from CHOTEAU (now CHOUTEAU). (Mont. Terr. Laws 1887, 15th leg., ext. sess., sec. 13/p. 109)

CASCADE became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

CASCADE gained from MEAGHER and exchanged small areas with MEAGHER along Smith River. (Mont. Laws 1897, 5th leg., pp. 50–52)

CASCADE lost to LEWIS AND CLARK. (Mont. Laws 1897, 5th leg., pp. 53–55)

CASCADE gained from MEAGHER. (Mont. Laws 1899, 6th leg., pp. 41–42)

CASCADE gained from MEAGHER. (Mont. Laws 1899, 6th leg., p. 43)

CASCADE gained from CHOTEAU (now CHOUTEAU). (Mont. Laws 1903, 8th leg., ch. 51/pp. 111–112)

CASCADE lost to creation of JUDITH BASIN. (Mont. Rev. Code 1921, sec. 4327/pp. 1584–1586; Burlingame, 17–20)

Part of CASCADE boundary with LEWIS AND CLARK placed on federal land survey line according to the CASCADE boundary description; change was not reflected in LEWIS AND CLARK description [no mappable change]. (Mont. Rev. Code 1921, secs. 4311, 4328/pp. 1563, 1586–1587)

CASCADE exchanged small areas with LEWIS AND CLARK. (Mont. Laws 1941, 27th leg., ch. 58/pp. 89–93)

CHOTEAU (now CHOUTEAU) created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 6/p. 676)

CHOTEAU (now CHOUTEAU) became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

CHOTEAU (now CHOUTEAU) re-created by Montana Territory; CHOTEAU lost to creation of EDGERTON (now LEWIS AND CLARK). (Mont. Terr. Laws 1864, 1st leg., sec. 8/p. 531)

CHOTEAU (now CHOUTEAU) lost to creation of MUSSELSHELL (original). This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 4/p. 6; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

CHOTEAU (now CHOUTEAU) gained part of MUSSELSHELL (original); MUSSELSHELL eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory. (U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

CHOTEAU (now CHOUTEAU) lost to re-creation of MEAGHER. (Mont. Terr. Laws 1867, 4th leg., pp. 99–100)

Part of CHOTEAU (now CHOUTEAU) reverted to non-county area. (Mont. Terr. Laws 1867, 4th leg., p. 129)

CHOTEAU (now CHOUTEAU) attached to LEWIS AND CLARK "for judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

CHOTEAU (now CHOUTEAU) boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 9/pp. 431–432)

CHOTEAU (now CHOUTEAU) gained from BIG HORN (original, now CUSTER) and DEER LODGE. (Mont. Terr. Laws 1876, 9th leg., pp. 46–47)

[1879] CHOTEAU (now CHOUTEAU) fully organized, detached from LEWIS AND CLARK. (History of Montana 1739–1885, p. 494)

CHOTEAU (now CHOUTEAU) boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 738/pp. 837–838)

CHOTEAU (now CHOUTEAU) lost to creation of CASCADE; CASCADE not fully organized, attached to CHOTEAU "for judicial purposes." Act passed 12 September 1887; took effect 19 December 1887. (Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105–109)

CASCADE fully organized, detached from CHOTEAU (now CHOUTEAU). (Mont. Terr. Laws 1887, 15th leg., ext. sess., sec. 13/p. 109)

CHOTEAU (now CHOUTEAU) lost to FERGUS. Act passed 14 March 1889; took effect 1 April 1889. (Mont. Terr. Laws 1889, 16th leg., pp. 232–233)

CHOTEAU (now CHOUTEAU) became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

CHOTEAU (now CHOUTEAU) lost to creation of TETON. Act passed 7 February 1893; took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 205–209)

CHOTEAU (now CHOUTEAU) lost to CASCADE. (Mont. Laws 1903, 8th leg., ch. 51/pp. 111–112)

Spelling of "CHOTEAU" changed to "CHOUTEAU." (Mont. Laws 1903, 8th leg., ch. 74/p. 147)

CHOUTEAU lost to creation of HILL. (Map of Hill County, 1912; Burlingame, 17–18)

CHOUTEAU lost to creation of BLAINE. (Mont. Rev. Code 1921, sec. 4307/pp. 1557–1559; Burlingame, 17–18)

CHOUTEAU lost to creation of PONDERA. Act passed 17 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 22/pp. 38–45)

CHOUTEAU lost to creation of LIBERTY. (Mont. Rev. Code 1921, sec. 4329/pp. 1587–1588; Burlingame, 17–20)

CHOUTEAU lost small area to creation of JUDITH BASIN when boundary was defined in terms of the federal land survey lines. (Mont. Rev. Code 1921, sec. 4327/pp. 1584–1586; Burlingame, 17–20)

CHOUTEAU lost to TETON. (Mont. Laws 1921, 17th leg., ch. 174/pp. 326–329)

CHOUTEAU lost small area to FERGUS when southern boundary was redefined to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4312/pp. 1564–1565)

CLACKAMAS District (Ore.) created by the Oregon Territory Provisional Government as one of the four original Oregon Territory counties. CLACKAMAS included all of present Montana west of the Continental Divide. (Swindler, 8:195; Holman, 7–9; Oregon Archives, 26)

CLACKAMAS District (Ore.) lost to non-county area; territory in present Montana was unchanged. (Ore. Laws, gen. and local, 1843–1849, p. 74)

CLACKAMAS District (Ore.) gained from CHAMPOEG (now MARION) District (Ore.); area within present Montana was unchanged. Boundary between CLACKAMAS and TUALITY (now WASHINGTON) District (Ore.) clarified [no change]. (Ore. Laws, gen. and local, 1843–1849, p. 36)

CLACKAMAS District (Ore.) became CLACKAMAS County when the Oregon Territory House of Representatives authorized substituting the word "County" for "District." (Ore. Laws, gen. and local, 1843–1849, p. 35)

CLACKAMAS (Ore.) lost to Canada when the Oregon Boundary Treaty between the United States and Great Britain established the northern boundary of Oregon Territory at 49 degrees north latitude; area within present Montana was unchanged. (Parry, 100:39–42; Van Zandt, 18)

CLACKAMAS (Ore.) lost to creation of Washington Territory; CLACKAMAS included a small area of present Montana south of 46 degrees north latitude and west of the Continental Divide. (U.S. Stat., vol. 10, ch. 90 [1853]/pp. 172–180; Van Zandt, 155)

CLACKAMAS (Ore.) lost to creation of WASCO (Ore.); CLACKAMAS eliminated from present Montana. (Ore. Terr. Laws 1853, 5th sess., spec., pp. 26–27)

BIG HORN (original, now CUSTER) created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 8/pp. 676–677)

BIG HORN (original, now CUSTER) became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

BIG HORN (original, now CUSTER) re-created by Montana Territory. BIG HORN gained all of DAWSON; DAWSON eliminated. BIG HORN not fully organized, attached to GALLATIN "for legislative and judicial purposes." (Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531)

BIG HORN (original, now CUSTER) lost to creation of MUSSELSHELL (original). This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 4/p. 6; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

BIG HORN (original, now CUSTER) gained part of MUSSELSHELL (original); MUSSELSHELL eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory. (U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

BIG HORN (original, now CUSTER) lost to creation of DAWSON. (Mont. Terr. Laws 1868, 5th leg., pp. 102–103)

Attachment of BIG HORN (original, now CUSTER) to GALLATIN "for judicial purposes" was confirmed. (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

BIG HORN (original, now CUSTER) gained from GALLATIN and gained non-county area (1), formerly part of CHOTEAU (now CHOUTEAU). BIG HORN remained attached to GALLATIN "for legislative and judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 20, secs. 8, 11/pp. 431–432)

BIG HORN (original, now CUSTER) lost to CHOTEAU (now CHOUTEAU). (Mont. Terr. Laws 1876, 9th leg., p. 47)

BIG HORN (original, now CUSTER) lost to MEAGHER. (Mont. Terr. Laws 1876, 9th leg., p. 48)

BIG HORN (original) renamed CUSTER. (Mont. Terr. Laws 1877, 10th leg., p. 425)

CUSTER fully organized, detached from GALLATIN. (History of Montana 1739–1885, p. 517)

DAWSON detached from MEAGHER, attached to CUSTER "for judicial and other purposes." (Mont. Terr. Laws 1881, 12th leg., p. 122)

CUSTER lost to GALLATIN. The area included all territory ceded by the Crow Indians to the United States on 12 June 1880; the United States Congress ratified the cession on 11 April 1882. Montana Territorial Legislature passed this act 14 February 1881 to take effect upon ratification of the treaty by the U. S. Congress. (Mont. Terr. Laws 1881, 12th leg., p. 124; Royce, 900–901, 904–905, pl. 39)

DAWSON fully organized, detached from CUSTER. (History of Montana 1739–1885, pp. 541–542)

CUSTER lost to creation of YELLOWSTONE; YELLOWSTONE not fully organized, attached to CUSTER "for judicial purposes." (Mont. Terr. Laws 1883, 13th leg., pp. 119–122)

CUSTER lost to DAWSON. (Mont. Terr. Laws 1883, 13th leg., p. 99)

YELLOWSTONE fully organized, detached from CUSTER. (Mont. Terr. Laws 1883, 13th leg., sec. 11/p. 122)

CUSTER lost part of the Crow Indian reservation, which was attached as a non-county area (2) to YELLOWSTONE "for judicial purposes." (Mont. Terr. Laws 1885, 14th leg., p. 74)

CUSTER boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., secs. 740, 742/pp. 838, 839–840)

CUSTER became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

CUSTER lost to creation of ROSEBUD. Act passed 11 February 1901; took effect 1 March 1901. (Mont. Laws 1901, 7th leg., pp. 97–101)

CUSTER lost to creation of FALLON. (Minutes of Board of County Commissioners, Custer County, 2 December 1913; Burlingame, 17–19)

CUSTER lost to creation of PRAIRIE. (Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17–19)

CUSTER lost to PRAIRIE. (Mont. Laws 1917, 15th leg., ch. 139/pp. 232–235)

CUSTER lost to creation of POWDER RIVER. Act passed 7 March 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 141/pp. 277–282)

CUSTER gained small area from PRAIRIE when boundary was adjusted to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4313/pp. 1566–1567)

The United States created Dakota Territory from Nebraska Territory and unorganized federal territory; included all of present Montana east of the Continental Divide. That part of Dakota Territory within present Montana was non-county area. (U.S. Stat., vol. 12, ch. 86 [1861]/pp. 239–244; Van Zandt, 134, 136–137)

Dakota Territory lost to creation of Idaho Territory. All of Dakota Territory was eliminated from present Montana. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808–814; Van Zandt, 134, 136, 156)

Dakota Territory gained from Idaho Territory; included a small area of about two square miles in present Montana that had been part of MADISON. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 18/p. 92; Van Zandt, 134–136, 156–157)

LARAMIE (Wyo.) created by Dakota Territory from non-county area; LARAMIE included the small non-county area of Dakota Territory in present Montana. (Dak. Terr. Laws 1866, 6th sess., ch. 14/p. 43)

The small remnant of Dakota Territory in present Montana again became non-county area when Wyoming Territory boundaries were established. (U.S. Stat., vol. 15, ch. 235 1868], secs. 1, 17/pp. 178, 183; Van Zandt, 136, 144)

Montana Territory gained the small remnant of Dakota Territory that remained between Montana and Wyoming Territories [see 3 March 1863]. (U.S. Stat., vol. 17, ch. 147 [1873]/p. 464; Van Zandt, 136, 145, 150)

DANIELS created by petition and election from SHERIDAN and VALLEY. (Mont. Rev. Code 1921, sec. 4314/pp. 1567–1568; Burlingame, 17–20)

DAWSON created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 7/p. 676)

DAWSON became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

DAWSON lost all territory to BIG HORN (original, now CUSTER); DAWSON eliminated. (Mont. Terr. Laws 1864, 1st leg., sec. 9/p. 531)

DAWSON re-created by Montana Territory from BIG HORN (original, now CUSTER). (Mont. Terr. Laws 1868, 5th leg., pp. 102–103)

DAWSON attached to MEAGHER "for judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

DAWSON boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 10/p. 432)

DAWSON lost to MEAGHER. (Mont. Terr. Laws 1876, 9th leg., p. 48)

DAWSON detached from MEAGHER, attached to CUSTER "for judicial and other purposes." (Mont. Terr. Laws 1881, 12th leg., p. 122)

DAWSON fully organized, detached from CUSTER. (History of Montana 1739–1885, pp. 541–542)

DAWSON gained from CUSTER. (Mont. Terr. Laws 1883, 13th leg., p. 99)

DAWSON boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 739/p. 838)

DAWSON lost to FERGUS. Act passed 14 March 1889; took effect 1 April 1889. (Mont. Terr. Laws 1889, 16th leg., pp. 232–233)

DAWSON became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

DAWSON lost to creation of VALLEY. Act passed 6 February 1893; took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 202–205)

DAWSON lost to creation of RICHLAND. (Minutes of Board of County Commissioners, Dawson County, 25–26 May 1914; Burlingame, 17–19)

DAWSON lost to creation of WIBAUX. (Minutes of Board of County Commissioners, Dawson County, 15 August 1914; Burlingame, 17–19)

DAWSON lost to creation of PRAIRIE. (Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17–19)

DAWSON exchanged with ROSEBUD when their common boundary was placed on federal land survey lines. (Mont. Laws 1917, 15th leg., ch. 36/pp. 38–39)

DAWSON lost small areas to PRAIRIE and WIBAUX when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1917, 15th leg., ch. 139/pp. 232–235)

DAWSON lost to creation of GARFIELD and McCONE. GARFIELD act passed 7 February 1919 and McCONE act passed 20 February 1919; both acts took effect 1 April 1919. (Mont. Laws 1919, 16th leg., chs. 4, 33/pp. 3–8, 68–75)

DEER LODGE created by Idaho Territory from IDAHO (Idaho), MISSOULA and non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 2/pp. 674–675)

DEER LODGE became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

DEER LODGE re-created by Montana Territory; DEER LODGE gained from BEAVERHEAD, JEFFERSON, and MADISON. (Mont. Terr. Laws 1864, 1st leg., sec. 2/p. 529)

DEER LODGE exchanged with MISSOULA. (Mont. Terr. Laws 1867, 4th leg., pp. 105–106)

DEER LODGE lost to EDGERTON (now LEWIS AND CLARK). (Mont. Terr. Laws 1867, 4th leg., p. 101)

DEER LODGE lost to JEFFERSON. (Mont. Terr. Laws 1867, 4th leg., pp. 104–105)

DEER LODGE boundaries redefined [no change]. (Mont. Terr. Laws 1867, 4th leg., sec. 1/p. 102)

DEER LODGE lost to MADISON. (Mont. Terr. Laws 1867, 4th leg., pp. 129–130)

DEER LODGE lost to MADISON. (Mont. Terr. Laws 1868, 5th leg., p. 105)

DEER LODGE exchanged with BEAVERHEAD. (Mont. Terr. Laws 1871, 7th leg., ch. 20, secs. 2–3/pp. 429–430)

DEER LODGE lost to CHOTEAU (now CHOUTEAU). (Mont. Terr. Laws 1876, 9th leg., pp. 46–47)

DEER LODGE lost to creation of SILVER BOW; SILVER BOW not fully organized, attached to DEER LODGE "for judicial purposes." (Mont. Terr. Laws 1881, 12th leg., pp. 85–88)

SILVER BOW fully organized, detached from DEER LODGE. (Mont. Terr. Laws 1881, 12th leg., sec. 11/p. 88)

DEER LODGE boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., secs. 731, 741/pp. 833–834, 838–839)

DEER LODGE became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

DEER LODGE exchanged with JEFFERSON. (Mont. Laws 1891, 2d leg., pp. 224–225)

DEER LODGE lost to creation of GRANITE. (Mont. Laws 1893, 3d leg., pp. 212–217)

DEER LODGE lost to FLATHEAD. (Mont. Laws 1899, 6th leg., p. 47)

DEER LODGE lost to LEWIS AND CLARK. Act passed 28 February 1899; took effect 1 June 1899. (Mont. Laws 1899, 6th leg., pp. 44–47)

DEER LODGE lost to creation of POWELL. (Mont. Laws 1901, 7th leg., pp. 101–106)

Legislature authorized DEER LODGE to be renamed DALY, and POWELL to be renamed DEER LODGE; change did not take effect. Montana Supreme Court ruled against the name change on 8 April 1901. (Mont. Laws 1901, 7th leg., pp. 107–110; "State ex rel. Sackett v. Thomas," in Mont. Rpts., 25:226–241)

DEER LODGE gained from SILVER BOW, exchanged with JEFFERSON. Act passed 4 March 1903; took effect 15 June 1903. (Mont. Laws 1903, 8th leg., ch. 62/pp. 127–130)

DEER LODGE lost to SILVER BOW. Act passed 13 February 1917; took effect 1 May 1917. (Mont. Laws 1917, 15th leg., ch. 21/pp. 22–24)

[May 1977] The city of Anaconda and the county of DEER LODGE formed a consolidated city/county government, but the county retained the name, DEER LODGE. (Deer Lodge County, http://rad.dli.state.mt.us/county/deerldg, 2 July 2004)

Territory between RICHLAND and WIBAUX was placed in dispute when both counties claimed the area [see 19 February 1915]. (Minutes of Board of County Commissioners, Dawson County, 15 August 1914; Burlingame, 17–19)

Disputed Area eliminated when the boundary between RICHLAND and WIBAUX was defined, settling boundary dispute dating from 17 August 1914. (Mont. Laws 1915, 14th leg., ch. 24/pp. 32–33)

FALLON created by petition and election from CUSTER. (Minutes of Board of County Commissioners, Custer County, 2 December 1913; Burlingame, 17–19)

FALLON lost to creation of WIBAUX. (Minutes of Board of County Commissioners, Dawson County, 15 August 1914; Burlingame, 17–19)

FALLON lost to creation of PRAIRIE. (Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17–19)

FALLON lost to creation of CARTER. (Mont. Laws 1917, 15th leg., ch. 56/pp. 71–76; "State ex rel. Ford v. Schofield," in Mont. Rpts., 53: 502–518)

FALLON exchanged with WIBAUX. (Mont. Laws 1919, 16th leg., ch. 185/pp. 351–352)

FERGUS created by Montana Territory from MEAGHER. Act passed 12 March 1885; took effect 1 December 1886. (Mont. Terr. Laws 1885, 14th leg., pp. 78–83)

FERGUS boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 743/p. 840)

FERGUS lost small area to creation of CASCADE and exchanged with MEAGHER. Act passed 12 September 1887; took effect 19 December 1887. (Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105–109)

FERGUS gained from CHOTEAU (now CHOUTEAU) and DAWSON. Act passed 14 March 1889; took effect 1 April 1889. (Mont. Terr. Laws 1889, 16th leg., pp. 232–233)

FERGUS became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

FERGUS boundaries redefined to correct oversight in Montana Political Code of 1895 [no change]. (Mont. Laws 1907, 10th leg., ch. 28/pp. 49–50)

FERGUS lost to creation of MUSSELSHELL and lost to MEAGHER. Act passed 11 February 1911; took effect 1 March 1911. (Mont. Laws 1911, 12th leg., ch. 25/pp. 29–38)

FERGUS lost to creation of JUDITH BASIN. (Mont. Rev. Code 1921, sec. 4327/pp. 1584–1586; Burlingame, 17–20)

FERGUS gained small area from CHOUTEAU when boundary was redefined to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4318/p. 1575)

FERGUS lost to creation of PETROLEUM. (Mont. Laws 1925, 19th leg., pp. 505–508)

FERGUS lost to JUDITH BASIN. (Mont. Laws 1925, 19th leg., ch. 93/pp. 125–130; "State ex rel. Foot v. Burr et al.," in Mont. Rpts., 73: 586–590)

FERGUS boundaries redefined to correct mistake in the 1935 and 1947 Revised Codes of Montana [no change]. (Mont. Laws 1951, 32d leg., ch. 173/pp. 342–349)

FLATHEAD created from MISSOULA. Act passed 6 February 1893; took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 198–201)

FLATHEAD gained from DEER LODGE. (Mont. Laws 1899, 6th leg., p. 47)

FLATHEAD lost to creation of LINCOLN. Act passed 9 March 1909; took effect 1 July 1909. (Mont. Laws 1909, 11th leg., ch. 133/pp. 193–199)

FLATHEAD exchanged with SANDERS, lost to MISSOULA and POWELL when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 42/pp. 58–59)

FLATHEAD lost to creation of LAKE. (Mont. Laws 1923, 18th leg., pp. 623–627)

GALLATIN created by Montana Territory from JEFFERSON and MADISON. BIG HORN (original, now CUSTER) not fully organized, attached to GALLATIN "for legislative and judicial purposes." (Mont. Terr. Laws 1864, 1st leg., secs. 7, 9/pp. 530–531)

GALLATIN lost to creation of MEAGHER. This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 10/pp. 11–12; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

GALLATIN gained all of MEAGHER; MEAGHER eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory. (U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

GALLATIN lost to re-creation of MEAGHER. (Mont. Terr. Laws 1867, 4th leg., pp. 99–100)

GALLATIN gained from JEFFERSON. (Mont. Terr. Laws 1867, 4th leg., pp. 104–105)

GALLATIN exchanged with MADISON. (Mont. Terr. Laws 1867, 4th leg., sec. 3/p. 103)

Attachment of BIG HORN (original, now CUSTER) to GALLATIN "for judicial purposes" was confirmed. (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

GALLATIN lost to BIG HORN (original, now CUSTER); BIG HORN remained attached to GALLATIN "for legislative and judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 20, secs. 8, 11/pp. 431–432)

GALLATIN gained small remnant of Dakota Territory that was transferred to Montana Territory on 17 February 1873. This act, which appears to have been based on faulty maps, assigned the area to BEAVERHEAD and MADISON; however, it was actually surrounded by GALLATIN. (Mont. Terr. Laws 1874, 8th leg., p. 68; Van Zandt, 136, 145, 150; De Lacy, Map of the Territory of Montana)

GALLATIN lost to MEAGHER. (Mont. Terr. Laws 1874, 8th leg., pp. 66–67)

CUSTER fully organized, detached from GALLATIN. (History of Montana 1739–1885, p. 517)

GALLATIN gained from CUSTER. The area included all territory ceded by the Crow Indians to the United States on 12 June 1880; the United States Congress ratified the cession on 11 April 1882. Montana Territorial Legislature passed this act 14 February 1881 to take effect upon ratification of the treaty by the U. S. Congress. (Mont. Terr. Laws 1881, 12th leg., p. 124; Royce, 900–901, 904–905, pl. 39)

GALLATIN lost to creation of YELLOWSTONE. (Mont. Terr. Laws 1883, 13th leg., pp. 119–122)

GALLATIN boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., secs. 737, 742/pp. 836–837, 839–840)

GALLATIN lost to creation of PARK; PARK not fully organized, attached to GALLATIN "for judicial purposes." GALLATIN lost that part of Yellowstone National Park located in Montana, which was excluded from county jurisdiction and became a non-county area. Act passed 23 February 1887; took effect 1 May 1887. (Mont. Terr. Laws 1887, 15th leg., pp. 1238–1242)

PARK fully organized, detached from GALLATIN. (Mont. Terr. Laws 1887, 15th leg., sec. 11/p. 1242)

GALLATIN became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

GALLATIN boundaries adjusted to run on federal land survey lines: GALLATIN exchanged with MADISON and PARK, gained small areas from BROADWATER and MEAGHER. (Mont. Laws 1913, 13th leg., ch. 60/pp. 113–116)

GALLATIN lost territory as the boundaries of Yellowstone National Park were expanded. County boundaries were defined to exclude land within Yellowstone National Park. (U.S. Stat., vol. 45, ch. 437 [1929]/pp. 1435–1436; Haines, 2: 325–331)

GALLATIN gained part of Yellowstone National Park, which had remained a non-county area in Montana. Act passed 19 April 1977; approved by GALLATIN voters 7 November 1978. (Mont. Laws 1977, 45th leg., ch. 447/pp. 1407–1411; Montana Code Annotated, "Descriptions—County Boundaries," 33)

GARFIELD created from DAWSON. Act passed 7 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 4/pp. 3–8)

GLACIER created from TETON. Act passed 17 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 21/pp. 32–38)

GOLDEN VALLEY created by petition and election from MUSSELSHELL and SWEET GRASS. (Mont. Rev. Code 1921, sec. 4323/pp. 1581–1582; Burlingame, 17–20)

GRANITE created from DEER LODGE, MISSOULA, and SILVER BOW. (Mont. Laws 1893, 3d leg., pp. 212–217)

GRANITE exchanged with MISSOULA. (Mont. Laws 1943, 28th leg., ch. 223/pp. 453–455)

HILL created by petition and election from CHOUTEAU. (Map of Hill County, 1912; Burlingame, 17–18)

HILL lost to creation of TOOLE. (Mont. Rev. Code 1921, sec. 4353/p. 1617; Burlingame, 17–19)

HILL lost to creation of LIBERTY. (Mont. Rev. Code 1921, sec. 4329/pp. 1587–1588; Burlingame, 17–20)

IDAHO (Idaho) created by Washington Territory from SHOSHONE (Idaho); included parts of present Montana, Idaho, and Wyoming. (Wash. Terr. Laws 1861, 9th sess., pp. 3–5)

IDAHO (Idaho) lost to creation of BOISE (Idaho); territory within present Montana was unchanged. (Wash. Terr. Laws 1862, 10th sess., pp. 3–4)

IDAHO (Idaho) became a county in Idaho Territory. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808–814; Van Zandt, 156)

IDAHO (Idaho) lost to re-creation of MISSOULA and to creation of DEER LODGE; IDAHO eliminated from present Montana. (Idaho Terr. Laws 1863, 1st sess., sec. 1/p. 674)

The United States created Idaho Territory from Dakota, Nebraska, and Washington Territories; included all of present Montana. Map depicts non-county areas of Idaho Territory in present Montana. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808–814; Van Zandt, 156)

Idaho Territory created counties throughout all of present Montana, eliminating all non-county areas. (Idaho Terr. Laws 1863, 1st sess., pp. 674–677)

JEFFERSON created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 5/pp. 675–676)

JEFFERSON became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

JEFFERSON re-created by Montana Territory; JEFFERSON lost to creation of EDGERTON (now LEWIS AND CLARK) and GALLATIN, and lost to DEER LODGE and BEAVERHEAD. (Mont. Terr. Laws 1864, 1st leg., sec. 5/p. 530)

JEFFERSON boundaries clarified [no change]. This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 19/p. 24; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

JEFFERSON exchanged with EDGERTON (now LEWIS AND CLARK). (Mont. Terr. Laws 1867, 4th leg., p. 101)

JEFFERSON gained from DEER LODGE, lost to GALLATIN. (Mont. Terr. Laws 1867, 4th leg., pp. 104–105)

JEFFERSON boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 5/p. 430)

JEFFERSON exchanged with SILVER BOW. (Mont. Terr. Laws 1883, 13th leg., p. 97)

JEFFERSON boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., secs. 734, 741/pp. 835, 838–839)

JEFFERSON became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

JEFFERSON exchanged with DEER LODGE. (Mont. Laws 1891, 2d leg., pp. 224–225)

JEFFERSON lost to creation of BROADWATER. Act passed 9 February 1897; took effect 1 March 1897. (Mont. Laws 1897, 5th leg., pp. 45–49)

JEFFERSON exchanged with DEER LODGE and exchanged small areas with POWELL. Act passed 4 March 1903; took effect 15 June 1903. (Mont. Laws 1903, 8th leg., ch. 62/pp. 127–130)

JUDITH BASIN created by petition and election from CASCADE, FERGUS, and a small area of CHOUTEAU. (Mont. Rev. Code 1921, sec. 4327/pp. 1584–1586; Burlingame, 17–20)

JUDITH BASIN gained from FERGUS. (Mont. Laws 1925, 19th leg., ch. 93, sec. 2/pp. 127–130; "State ex rel. Foot v. Burr et al.," in Mont. Rpts., 73: 586–590)

JUDITH BASIN boundaries redefined to correct mistake in the 1935 and 1947 Revised Codes of Montana [no change]. (Mont. Laws 1951, 32d leg., ch. 173/pp. 342–349)

LAKE created by petition and election from FLATHEAD and MISSOULA. (Mont. Laws 1923, 18th leg., pp. 623–627)

LARAMIE (Wyo.) created by Dakota Territory from non-county area; included all of present Wyoming that was then part of Dakota Territory, plus a small area of present Montana. (Dak. Terr. Laws 1866, 6th sess., ch. 14/p. 43)

LARAMIE (Wyo.) lost to creation of CARTER (Wyo., now SWEETWATER); LARAMIE eliminated from present Montana. (Dak. Terr. Laws 1867, 7th sess., ch. 7/pp. 122–123)

EDGERTON (now LEWIS AND CLARK) created by Montana Territory from CHOTEAU (now CHOUTEAU) and JEFFERSON. (Mont. Terr. Laws 1864, 1st leg., sec. 6/p. 530)

EDGERTON (now LEWIS AND CLARK) gained from DEER LODGE, exchanged with JEFFERSON. (Mont. Terr. Laws 1867, 4th leg., p. 101)

EDGERTON renamed LEWIS AND CLARK; legislation used the spelling "LEWIS AND CLARKE" [see act of 10 February 1905]. Act passed 20 December 1867; took effect 1 March 1868. (Mont. Terr. Laws 1867, 4th leg., p. 130)

CHOTEAU (now CHOUTEAU) attached to LEWIS AND CLARK "for judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

LEWIS AND CLARK boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 6/pp. 430–431)

[1879] CHOTEAU (now CHOUTEAU) fully organized, detached from LEWIS AND CLARK. (History of Montana 1739–1885, p. 494)

LEWIS AND CLARK boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 735/pp. 835–836)

LEWIS AND CLARK lost to creation of CASCADE [LEWIS AND CLARKE spelling used in this act]. Act passed 12 September 1887; took effect 19 December 1887. (Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105–109)

LEWIS AND CLARK became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

LEWIS AND CLARK gained from BROADWATER, CASCADE, and MEAGHER [LEWIS AND CLARKE spelling used in this act]. (Mont. Laws 1897, 5th leg., pp. 53–55)

LEWIS AND CLARK gained from DEER LODGE. Act passed 28 February 1899; took effect 1 June 1899 [LEWIS AND CLARKE spelling used in this act]. (Mont. Laws 1899, 6th leg., pp. 44–47)

LEWIS AND CLARK lost to POWELL [LEWIS AND CLARKE spelling used in this act]. (Mont. Laws 1903, 8th leg., ch. 106/pp. 196–197)

Spelling of LEWIS AND CLARK officially established as "CLARK," not "CLARKE." (Mont. Laws 1905, 9th leg., ch. 13/p. 28)

Part of LEWIS AND CLARK boundary with CASCADE placed on federal land survey line according to the CASCADE boundary description; change was not reflected in LEWIS AND CLARK description [no mappable change]. (Mont. Rev. Code 1921, secs. 4311, 4328/pp. 1563, 1586–1587)

LEWIS AND CLARK exchanged small areas with CASCADE. (Mont. Laws 1941, 27th leg., ch. 58/pp. 89–93)

LIBERTY created by petition and election from CHOUTEAU and HILL. (Mont. Rev. Code 1921, sec. 4329/pp. 1587–1588; Burlingame, 17–20)

LINCOLN created from FLATHEAD. Act passed 9 March 1909; took effect 1 July 1909. (Mont. Laws 1909, 11th leg., ch. 133/pp. 193–199)

LINCOLN lost to SANDERS. (Mont. Laws 1913, 13th leg., ch. 46/pp. 66–67)

McCONE created from DAWSON and RICHLAND. Act passed 20 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 33/pp. 68–75)

MADISON created by Idaho Territory from non-county area. (Idaho Terr. Laws 1863, 1st sess., sec. 4/p. 675)

MADISON lost small area of about two square miles to Dakota Territory when Dakota Territory gained from Idaho Territory. MADISON became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

MADISON re-created by Montana Territory; MADISON lost to BEAVERHEAD and DEER LODGE, and lost to creation of GALLATIN. (Mont. Terr. Laws 1864, 1st leg., sec. 4/p. 529)

MADISON boundaries redefined [no change]. This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 22/pp. 25–26; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MADISON gained from BEAVERHEAD, exchanged with GALLATIN. (Mont. Terr. Laws 1867, 4th leg., sec. 3/p. 103)

MADISON gained from DEER LODGE. (Mont. Terr. Laws 1867, 4th leg., pp. 129–130)

MADISON gained from BEAVERHEAD and DEER LODGE. (Mont. Terr. Laws 1868, 5th leg., p. 105)

MADISON boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 4/p. 430)

MADISON authorized to gain part of the remnant of Dakota Territory that was transferred to Montana Territory on 17 February 1873. This act appears to have been based on faulty maps, since the area was actually surrounded by GALLATIN [no change]. (Mont. Terr. Laws 1874, 8th leg., p. 68; Van Zandt, 136, 145, 150; De Lacy, Map of the Territory of Montana)

MADISON boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 733/pp. 834–835)

MADISON became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

MADISON lost to BEAVERHEAD. (Mont. Laws 1911, 12th leg., ch. 73/pp. 137–141)

MADISON exchanged with GALLATIN when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 60/pp. 113–116)

MEAGHER created by Montana Territory from GALLATIN. This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 10/pp. 11–12; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MEAGHER lost all territory to GALLATIN; MEAGHER eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory. (U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MEAGHER re-created from CHOTEAU (now CHOUTEAU) and GALLATIN. (Mont. Terr. Laws 1867, 4th leg., pp. 99–100)

DAWSON attached to MEAGHER "for judicial purposes." (Mont. Terr. Laws 1871, 7th leg., ch. 77/p. 585)

MEAGHER boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 7/p. 431)

MEAGHER gained from GALLATIN. (Mont. Terr. Laws 1874, 8th leg., pp. 66–67)

MEAGHER gained from BIG HORN (original, now CUSTER) and DAWSON. (Mont. Terr. Laws 1876, 9th leg., p. 48)

DAWSON detached from MEAGHER, attached to CUSTER "for judicial and other purposes." (Mont. Terr. Laws 1881, 12th leg., p. 122)

MEAGHER boundaries redefined [no change]. (Mont. Terr. Laws 1883, 13th leg., p. 33)

MEAGHER lost to creation of FERGUS. Act passed 12 March 1885; took effect 1 December 1886. (Mont. Terr. Laws 1885, 14th leg., pp. 78–83)

MEAGHER boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., secs. 736, 743/pp. 836, 840)

MEAGHER lost to creation of CASCADE and exchanged with FERGUS. Act passed 12 September 1887; took effect 19 December 1887. (Mont. Terr. Laws 1887, 15th leg., ext. sess., pp. 105–109)

MEAGHER became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

MEAGHER lost to creation of SWEET GRASS and lost to YELLOWSTONE. (Mont. Laws 1895, 4th leg., pp. 54–58)

MEAGHER lost to creation of BROADWATER. Act passed 9 February 1897; took effect 1 March 1897. MEAGHER lost to CASCADE and exchanged small areas with CASCADE along Smith River. (Mont. Laws 1897, 5th leg., pp. 45–52)

MEAGHER lost to LEWIS AND CLARK. (Mont. Laws 1897, 5th leg., pp. 53–55)

MEAGHER lost to CASCADE. (Mont. Laws 1899, 6th leg., pp. 41–42)

MEAGHER lost to CASCADE. (Mont. Laws 1899, 6th leg., p. 43)

MEAGHER lost to creation of MUSSELSHELL, gained from FERGUS, and lost to BROADWATER. Act passed 11 February 1911; took effect 1 March 1911. (Mont. Laws 1911, 12th leg., ch. 25/pp. 29–38)

MEAGHER lost small area to GALLATIN when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 60/pp. 113–116)

MEAGHER lost to creation of WHEATLAND. Act passed 22 February 1917; took effect 1 April 1917. (Mont. Laws 1917, 15th leg., ch. 55/pp. 63–70)

MEAGHER exchanged with PARK when boundary was adjusted to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4333/pp. 1592–1593)

MINERAL created by petition and election from MISSOULA. (Mont. Rev. Code 1921, sec. 4334/pp. 1593–1594; Burlingame, 17–19)

MISSOULA created by Washington Territory from SPOKANE (Wash. Terr., original, extinct); included parts of present Idaho and Montana. (Wash. Terr. Laws 1860, 8th sess., pp. 7–8)

MISSOULA lost to SHOSHONE (Idaho) and lost to creation of NEZ PERCE (Idaho); area within present Montana was unchanged. (Wash. Terr. Laws 1861, 9th sess., pp. 3–5)

MISSOULA became a county in Idaho Territory. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808–814; Van Zandt, 156)

MISSOULA re-created by Idaho Territory. MISSOULA gained from IDAHO (Idaho) and non-county areas, lost to creation of DEER LODGE. (Idaho Terr. Laws 1863, 1st sess., sec. 1/p. 674)

MISSOULA became a county in Montana Territory. On 22 September 1864, Montana Territorial Governor, Sidney Edgerton, recognized the counties created by Idaho Territory in an election proclamation. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85–92; Sanders, Helen F., 1:329; Van Zandt, 145)

MISSOULA re-created by Montana Territory with no change in boundaries. (Mont. Terr. Laws 1864, 1st leg., sec. 1/p. 528)

MISSOULA exchanged with DEER LODGE. (Mont. Terr. Laws 1867, 4th leg., pp. 105–106)

MISSOULA boundaries redefined [no change]. (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 1/pp. 428–429)

MISSOULA boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 730/p. 833)

MISSOULA became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

MISSOULA lost to creation of FLATHEAD and TETON. Acts passed 6 February and 7 February 1893, respectively; both took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 198–201, 205–209)

MISSOULA lost to creation of GRANITE. (Mont. Laws 1893, 3d leg., pp. 212–217)

MISSOULA lost to creation of RAVALLI. Acts passed 16 February and 2 March 1893; took effect 1 April 1893. (Mont. Laws 1893, 3d leg., pp. 209–213)

MISSOULA lost to creation of SANDERS. Act passed 7 February 1905; took effect 1 March 1906. (Mont. Laws 1905, 9th leg., ch. 9/pp. 18–24)

MISSOULA exchanged with SANDERS. (Mont. Laws 1911, 12th leg., ch. 54/pp. 90–91)

MISSOULA gained from FLATHEAD when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 42/pp. 58–59)

MISSOULA lost to creation of MINERAL. (Mont. Rev. Code 1921, sec. 4334/pp. 1593–1594; Burlingame, 17–19)

MISSOULA gained from POWELL. (Mont. Laws 1915, 14th leg., ch. 46/pp. 69–70)

MISSOULA lost to creation of LAKE. (Mont. Laws 1923, 18th leg., pp. 623–627)

MISSOULA exchanged with GRANITE. (Mont. Laws 1943, 28th leg., ch. 223/pp. 453–455)

That part of present Montana east of the Continental Divide and south of the Missouri River became non-county area in Missouri Territory. (Terr. Papers U.S., 14:599–601; U.S. Stat., vol. 2, ch. 95 [1812]/pp. 743–747)

All of ST. CHARLES (Mo.) in present Montana reverted to non-county area in Missouri Territory. (Mo. Laws Pub. and Gen., 1:ch. 99/pp. 293–295)

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

Montana Territory gained the small remnant of Dakota Territory that remained between Montana and Wyoming Territories [see Dakota Territory, 26 May 1864]. (U.S. Stat., vol. 17, ch. 147 [1873]/p. 464; Van Zandt, 136, 145, 150)

MUSSELSHELL (original) created by Montana Territory from BIG HORN (original, now CUSTER) and CHOTEAU (now CHOUTEAU). This act passed by the 2d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 2d leg., ch. 4/p. 6; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MUSSELSHELL (original) authorized to be renamed VIVION [change did not take effect]. This act passed by the 3d territorial legislature. All acts of this legislature were declared null and void by the United States Congress on 2 March 1867. (Mont. Terr. Laws 1866, 3d leg., ch. 25/p. 77; U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MUSSELSHELL (original) lost all territory to BIG HORN (original, now CUSTER) and CHOTEAU (now CHOUTEAU); MUSSELSHELL eliminated when the United States Congress declared null and void all acts passed by the 2d and 3d legislative assemblies of Montana Territory. (U.S. Stat., vol. 14, ch. 150 [1867], sec. 6/p. 427; Burlingame and Toole, 1:219–228; Sanders, Helen F., 1:331–341)

MUSSELSHELL created from FERGUS, MEAGHER, and YELLOWSTONE. Act passed 11 February 1911; took effect 1 March 1911. (Mont. Laws 1911, 12th leg., ch. 25/pp. 29–38)

MUSSELSHELL exchanged with ROSEBUD. (Mont. Laws 1917, 15th leg., ch. 108/pp. 177–178)

MUSSELSHELL lost to creation of GOLDEN VALLEY. (Mont. Rev. Code 1921, sec. 4323/pp. 1581–1582; Burlingame, 17–20)

The United States created Nebraska Territory from unorganized federal territory; included all of present Montana east of the Continental Divide. Nebraska Territory created no counties in present Montana. (U.S. Stat., vol. 10, ch. 59 [1854]/pp. 277–290; Van Zandt, 136)

Nebraska Territory lost to creation of Dakota Territory; Nebraska Territory eliminated from present Montana. (U.S. Stat., vol. 12, ch. 86 [1861]/pp. 239–244; Van Zandt, 134, 136–137)

Part of CHOTEAU (now CHOUTEAU) reverted to non-county area (1). (Mont. Terr. Laws 1867, 4th leg., p. 129)

Non-county area (1), formerly part of CHOTEAU (now CHOUTEAU), was eliminated when it became part of BIG HORN (original, now CUSTER). (Mont. Terr. Laws 1871, 7th leg., ch. 20, sec. 11/p. 432)

Part of the Crow Indian reservation was removed from CUSTER and became a non-county area (2) attached to YELLOWSTONE "for judicial purposes." (Mont. Terr. Laws 1885, 14th leg., p. 74)

Crow Indians ceded territory to the United States, which was added to YELLOWSTONE. The unceded portion of the Crow Reservation west of the Big Horn River remained attached to YELLOWSTONE as non-county area (2). (Royce, 942–943, pl. 40; U.S. Stat., vol. 26, ch. 543, art. 6, secs. 31–38/pp. 1039–1044)

YELLOWSTONE gained all that part of the Crow Indian reservation lying west of the Big Horn River; non-county area (2) eliminated. (Mont. Laws 1897, 5th leg., p. 55)

Present Montana west of the Continental Divide was part of the Oregon Country, which was claimed by both the United States and Great Britain. (Paullin, 36–37, 61; Van Zandt, 153)

The establishment of the Oregon Territory Provisional Government strengthened United States' control over the Oregon Country, although final settlement with Great Britain was not made until 15 June 1846. (Loy, 16)

PARK created by Montana Territory from GALLATIN; PARK not fully organized, attached to GALLATIN "for judicial purposes." Act passed 23 February 1887; took effect 1 May 1887. (Mont. Terr. Laws 1887, 15th leg., pp. 1238–1242)

PARK fully organized, detached from GALLATIN. (Mont. Terr. Laws 1887, 15th leg., sec. 11/p. 1242)

PARK became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

PARK lost to creation of SWEET GRASS. (Mont. Laws 1895, 4th leg., pp. 54–58)

PARK lost to creation of CARBON. Act passed 4 March 1895; took effect 1 May 1895. (Mont. Laws 1895, 4th leg., pp. 49–54)

PARK exchanged with GALLATIN when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 60/pp. 113–116)

PARK exchanged with MEAGHER when boundary was adjusted to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4337/pp. 1598–1599)

PARK lost territory as the boundaries of Yellowstone National Park were expanded. County boundaries were defined to exclude land within Yellowstone National Park. (U.S. Stat., vol. 45, ch. 437 [1929]/pp. 1435–1436; Haines, 2: 325–331)

PARK lost territory as the boundaries of Yellowstone National Park were expanded to include an area known as the "Game Ranch." County boundaries were defined to exclude land within Yellowstone National Park. (Haines, 2: 331–333; U.S. Stat., vol. 44, ch. 399 [1926]/pp. 655–657)

PARK gained part of Yellowstone National Park, which had remained a non-county area in Montana. Act passed 19 April 1977; approved by PARK voters 7 November 1978. (Mont. Laws 1977, 45th leg., ch. 447/pp. 1407–1411; Montana Code Annotated, "Descriptions—County Boundaries," 62)

PETROLEUM created by petition and election from FERGUS. (Mont. Laws 1925, 19th leg., pp. 505–508; "State ex rel. Foot v. Burr et al.," in Mont. Rpts., 73: 586–590)

PHILLIPS created by petition and election from BLAINE and VALLEY. (Mont. Rev. Code 1921, sec. 4338/pp. 1599–1601; Burlingame, 17–19)

PONDERA created from CHOUTEAU and TETON. Act passed 17 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 22/pp. 38–45)

POWDER RIVER created from CUSTER. Act passed 7 March 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 141/pp. 277–282)

Boundary between POWDER RIVER and CARTER clarified [no change]. (Mont. Laws 1929, 21st leg., ch. 45/pp. 75–76)

POWELL created from DEER LODGE. (Mont. Laws 1901, 7th leg., pp. 101–106)

Legislature authorized POWELL to be renamed DEER LODGE, and DEER LODGE to be renamed DALY; change did not take effect. Montana Supreme Court ruled against the name change on 8 April 1901. (Mont. Laws 1901, 7th leg., pp. 107–110; "State ex rel. Sackett v. Thomas," in Mont. Rpts., 25:226–241)

POWELL gained from LEWIS AND CLARK. (Mont. Laws 1903, 8th leg., ch. 106/pp. 196–197)

POWELL exchanged small areas with JEFFERSON. Act passed 4 March 1903; took effect 15 June 1903. (Mont. Laws 1903, 8th leg., ch. 62/pp. 127–130)

POWELL gained from FLATHEAD when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 42/pp. 58–59)

POWELL lost to MISSOULA. (Mont. Laws 1915, 14th leg., ch. 46/pp. 69–70)

PRAIRIE created by petition and election from CUSTER, DAWSON, and FALLON. (Minutes of Board of County Commissioners, Dawson County, 4 February 1915; Burlingame, 17–19)

PRAIRIE gained from CUSTER. PRAIRIE gained small area from DAWSON and lost small area to WIBAUX when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1917, 15th leg., ch. 139/pp. 232–235)

PRAIRIE lost small area to CUSTER when boundary was adjusted to run on federal land survey lines. (Mont. Rev. Code 1921, sec. 4342/pp. 1603–1605)

RAVALLI created from MISSOULA. Acts passed 16 February and 2 March 1893; took effect 1 April 1893. (Mont. Laws 1893, 3d leg., pp. 209–213)

RICHLAND created by petition and election from DAWSON. (Minutes of Board of County Commissioners, Dawson County, 25–26 May 1914; Burlingame, 17–19)

Boundary between RICHLAND and WIBAUX was defined, settling boundary dispute dating from 17 August 1914. (Mont. Laws 1915, 14th leg., ch. 24/pp. 32–33)

RICHLAND lost to creation of McCONE. Act passed 20 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 33/pp. 68–75)

ROOSEVELT created from SHERIDAN. (Mont. Laws 1919, 16th leg., ch. 23/pp. 45–50)

ROOSEVELT boundary along Missouri River clarified [no change]. (Mont. Rev. Code 1921, sec. 4345/p. 1606)

ROSEBUD created from CUSTER. Act passed 11 February 1901; took effect 1 March 1901. (Mont. Laws 1901, 7th leg., pp. 97–101)

ROSEBUD lost to creation of BIG HORN. (Mont. Rev. Code 1921, sec. 4306/pp. 1556–1557; Burlingame, 17–18)

ROSEBUD exchanged with DAWSON when their common boundary was placed on federal land survey lines. (Mont. Laws 1917, 15th leg., ch. 36/pp. 38–39)

ROSEBUD exchanged with MUSSELSHELL and YELLOWSTONE. (Mont. Laws 1917, 15th leg., chs. 108, 159/pp. 177–178, 404–405)

ROSEBUD lost to creation of TREASURE. Act passed 7 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., ch. 5/pp. 8–15)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. The portion of present Montana 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. CHARLES (Mo.) District was created by the District of Louisiana to include a vast area between the Mississippi River and the Rocky Mountains, which encompassed all or part of six present states and part of Canada. That part of present Montana within the District of Louisiana and north of the Missouri River was part of ST. CHARLES District. (U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283–289; Terr. Papers U.S., 13:51–52)

The District of Louisiana was renamed Louisiana Territory and was fully organized as a separate territory. ST. CHARLES (Mo.) District became a district (county) in Louisiana Territory; boundaries were unchanged. (U.S. Stat., vol. 2, ch. 31 [1805]/pp. 331–332)

Louisiana Territory was renamed Missouri Territory. ST. CHARLES (Mo.) became a county in Missouri Territory; boundaries were unchanged. (Terr. Papers U.S., 14:599–601; U.S. Stat., vol. 2, ch. 95 [1812]/pp. 743–747)

Most of ST. CHARLES (Mo.) reverted to non-county area in Missouri Territory; ST. CHARLES (Mo.) eliminated from present Montana. (Mo. Laws Pub. and Gen., 1:ch. 99/pp. 293–295)

The United States divided the Louisiana Purchase at the parallel of 33 degrees north latitude into the District of Louisiana and Orleans Territory. The portion of present Montana 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 (Mo.) District was created by the District of Louisiana to include a vast area between the Mississippi River and the Rocky Mountains, which encompassed all or part of eight present states. That part of present Montana within the District of Louisiana and south of the Missouri River was part of ST. LOUIS District. (U.S. Stat., vol. 2, ch. 38 [1804]/pp. 283–289; Terr. Papers U.S., 13:51–52)

The District of Louisiana was renamed Louisiana Territory and was fully organized as a separate territory. ST. LOUIS (Mo.) District became a district (county) in Louisiana Territory; boundaries were unchanged. (U.S. Stat., vol. 2, ch. 31 [1805]/pp. 331–332)

Louisiana Territory was renamed Missouri Territory. Most of ST. LOUIS (Mo.) reverted to non-county area in Missouri Territory, including the part in present Montana; ST. LOUIS (Mo.) eliminated from present Montana. (Terr. Papers U.S., 14:599–601; U.S. Stat., vol. 2, ch. 95 [1812]/pp. 743–747)

SANDERS created from MISSOULA. Act passed 7 February 1905; took effect 1 March 1906. (Mont. Laws 1905, 9th leg., ch. 9/pp. 18–24)

SANDERS exchanged with MISSOULA. (Mont. Laws 1911, 12th leg., ch. 54/pp. 90–91)

SANDERS exchanged with FLATHEAD when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1913, 13th leg., ch. 42/pp. 58–59)

SANDERS gained from LINCOLN. (Mont. Laws 1913, 13th leg., ch. 46/pp. 66–67)

SHERIDAN created by petition and election from VALLEY. (Sheridan County Commissioner's Journal Transcribed, 21 March 1913, pp. 87–88; Burlingame, 17–18)

SHERIDAN lost to creation of ROOSEVELT. (Mont. Laws 1919, 16th leg., ch. 23/pp. 45–50)

SHERIDAN lost to creation of DANIELS. (Mont. Rev. Code 1921, sec. 4314/pp. 1567–1568; Burlingame, 17–20)

SHOSHONE (Idaho) created by Washington Territory from SPOKANE (Wash. Terr., original, extinct) and non-county area; included parts of present Idaho, Montana, and Wyoming. (Wash. Terr. Laws 1860, 8th sess., pp. 13–14)

SHOSHONE (Idaho) lost to Nebraska Territory; area within present Montana was unchanged. (U.S. Stat., vol. 12, ch. 86 [1861]/pp. 239–244; Van Zandt, 134, 136–137)

SHOSHONE (Idaho) gained from MISSOULA and SPOKANE (Wash. Terr., original, extinct), lost to creation of IDAHO (Idaho) and NEZ PERCE (Idaho). SHOSHONE eliminated from present Montana. (Wash. Terr. Laws 1861, 9th sess., pp. 3–5)

SILVER BOW created by Montana Territory from DEER LODGE; SILVER BOW not fully organized, attached to DEER LODGE "for judicial purposes." (Mont. Terr. Laws 1881, 12th leg., pp. 85–88)

SILVER BOW fully organized, detached from DEER LODGE. (Mont. Terr. Laws 1881, 12th leg., sec. 11/p. 88)

SILVER BOW exchanged with JEFFERSON. (Mont. Terr. Laws 1883, 13th leg., p. 97)

SILVER BOW boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 741/pp. 838–839)

SILVER BOW became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

SILVER BOW lost to creation of GRANITE. (Mont. Laws 1893, 3d leg., pp. 212–217)

SILVER BOW lost to DEER LODGE. Act passed 4 March 1903; took effect 15 June 1903. (Mont. Laws 1903, 8th leg., ch. 62/pp. 127–130)

SILVER BOW gained from DEER LODGE. Act passed 13 February 1917; took effect 1 May 1917. (Mont. Laws 1917, 15th leg., ch. 21/pp. 22–24)

Legislature authorized the governmental consolidation of SILVER BOW and the city of Butte into "The City and County of Butte," subject to the approval of voters; change did not take effect. (Mont. Laws 1931, 22d leg., ch. 2/pp. 5–37)

[1977] The city of Butte and the county of SILVER BOW formed a consolidated city/county government, but the county retained the name, SILVER BOW. (City and County of Butte-Silver Bow, http://www.co.silverbow.mt.us, 2 July 2004; correspondence, Butte Public Library, 29 June 2004)

SKAMANIA (Wash.) created by Washington Territory from CLARK (Wash.), LEWIS (Wash.), and non-county area; included parts of present Washington, Idaho, and Montana. (Wash. Terr. Laws 1854, 1st sess., p. 473; Abbott and Carver, 23)

SKAMANIA (Wash.) lost to creation of WALLA WALLA (Wash.); SKAMANIA eliminated from present Montana. (Wash. Terr. Laws 1854, 1st sess., pp. 472–473; Abbott and Carver, 23)

SPOKANE (Wash. Terr., original, extinct) created by Washington Territory from WALLA WALLA (Wash.); SPOKANE included parts of present Washington, Idaho, and Montana. (Wash. Terr. Laws 1857, 5th sess., p. 51; Scott and De Lorme, 39)

SPOKANE (Wash. Terr., original, extinct) lost to creation of MISSOULA. (Wash. Terr. Laws 1860, 8th sess., pp. 7–8)

SPOKANE (Wash. Terr., original, extinct) lost to creation of SHOSHONE (Idaho); area within present Montana was unchanged. (Wash. Terr. Laws 1860, 8th sess., pp. 13–14)

SPOKANE (Wash. Terr., original, extinct) lost to SHOSHONE (Idaho) and lost to creation of NEZ PERCE (Idaho); area within present Montana was unchanged. (Wash. Terr. Laws 1861, 9th sess., pp. 4–5)

SPOKANE (Wash. Terr., original, extinct) was reduced when Idaho Territory was created from Dakota, Nebraska, and Washington Territories; SPOKANE eliminated from present Montana. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808–814; Van Zandt, 156)

STILLWATER created by petition and election from CARBON, SWEET GRASS, and YELLOWSTONE. (Mont. Rev. Code 1921, sec. 4350/pp. 1612–1614; Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102; Burlingame, 17–18)

STILLWATER exchanged with SWEET GRASS. (Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102)

SWEET GRASS created from MEAGHER, PARK, and YELLOWSTONE. (Mont. Laws 1895, 4th leg., pp. 54–58)

SWEET GRASS lost to creation of STILLWATER. (Mont. Rev. Code 1921, sec. 4350/pp. 1612–1614; Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102; Burlingame, 17–18)

SWEET GRASS exchanged with STILLWATER. (Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102)

SWEET GRASS lost to creation of STILLWATER. SWEET GRASS lost to creation of WHEATLAND. Act passed 22 February 1917; took effect 1 April 1917. (Mont. Laws 1917, 15th leg., ch. 55/pp. 63–70)

SWEET GRASS lost to creation of GOLDEN VALLEY. (Mont. Rev. Code 1921, sec. 4323/pp. 1581–1582; Burlingame, 17–20)

TETON created from CHOTEAU (now CHOUTEAU) and MISSOULA. Act passed 7 February 1893; took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 205–209)

TETON lost to creation of TOOLE. (Mont. Rev. Code 1921, sec. 4353/p. 1617; Burlingame, 17–19)

SWEET GRASS lost to creation of STILLWATER. TETON lost to creation of GLACIER and PONDERA. Both acts passed 17 February 1919; took effect 1 April 1919. (Mont. Laws 1919, 16th leg., chs. 21–22/pp. 32–45)

TETON gained from CHOUTEAU. (Mont. Laws 1921, 17th leg., ch. 174/pp. 326–329)

TOOLE created by petition and election from HILL and TETON. (Mont. Rev. Code 1921, sec. 4353/p. 1617; Burlingame, 17–19)

SWEET GRASS lost to creation of STILLWATER. TREASURE created from ROSEBUD. Act passed 7 February 1919; took effect 1 April 1919. Mistake in description corrected in 1921 Montana Revised Code. (Mont. Laws 1919, 16th leg., ch. 5/pp. 8–15)

TREASURE boundaries redefined to correct mistake of 1 April 1919 [no change]. (Mont. Rev. Code 1921, sec. 4354/pp. 1617–1619)

All of present Montana east of the Continental Divide (formerly Missouri Territory) became part of unorganized federal territory (non-county area). (U.S. Stat., vol. 3, ch. 22 [1820]/pp. 545–548 and res. 1 [1821]/p. 645; Van Zandt, 117)

The United States created Nebraska Territory from unorganized federal territory, eliminating unorganized federal territory. (U.S. Stat., vol. 10, ch. 59 [1854]/pp. 277–290; Van Zandt, 136)

VALLEY created from DAWSON. Act passed 6 February 1893; took effect 1 March 1893. (Mont. Laws 1893, 3d leg., pp. 202–205)

VALLEY lost to creation of SHERIDAN. (Sheridan County Commissioner's Journal Transcribed, 21 March 1913, pp. 87–88; Burlingame, 17–18)

VALLEY lost to creation of PHILLIPS. (Mont. Rev. Code 1921, sec. 4338/pp. 1599–1601; Burlingame, 17–19)

VALLEY lost to creation of DANIELS. (Mont. Rev. Code 1921, sec. 4314/pp. 1567–1568; Burlingame, 17–20)

WALLA WALLA (Wash.) created by Washington Territory from SKAMANIA (Wash.) and non-county area; included parts of present Washington, Idaho, and Montana. WALLA WALLA overlapped territory also claimed by WHATCOM (Wash.). (Wash. Terr. Laws 1854, 1st sess., pp. 472–473; Abbott and Carver, 23)

WALLA WALLA (Wash.) lost to creation of SPOKANE (Wash. Terr., original, extinct); WALLA WALLA eliminated from present Montana. (Wash. Terr. Laws 1857, 5th sess., p. 51; Scott and De Lorme, 39)

WASCO (Ore.) created by Oregon Territory from CLACKAMAS (Ore.), JACKSON (Ore.), LANE (Ore.), LINN (Ore.), and MARION (Ore.); WASCO included territory in present Oregon, Idaho, Wyoming, and a small part of Montana. (Ore. Terr. Laws 1853, 5th sess., spec., pp. 26–27)

Boundary between WASCO (Ore.) and MULTNOMAH (Ore.) adjusted near the Columbia River [change too small to map]; area within present Montana was unchanged. (Ore. Terr. Laws 1856, 8th sess., pp. 78–79)

WASCO (Ore.) boundaries reduced when Oregon became a state; WASCO eliminated from present Montana. (U.S. Stat., vol. 11, ch. 33 [1859]/pp. 383–384; Van Zandt, 153–155)

The United States created Washington Territory from Oregon Territory; Washington Territory included all of present Montana west of the Continental Divide and north of 46 degrees north latitude as a non-county area. (U.S. Stat., vol. 10, ch. 90 [1853]/pp. 172–180; Van Zandt, 155)

That part of Washington Territory (non-county area) in present Montana lost to creation of SKAMANIA (Wash.). (Wash. Terr. Laws 1854, 1st sess., p. 473; Abbott and Carver, 23)

That part of Washington Territory (non-county area) in present Montana lost to creation of WALLA WALLA (Wash.); eliminated all non-county areas of Washington Territory in present Montana. (Wash. Terr. Laws 1854, 1st sess., pp. 472–473; Abbott and Carver, 23)

Washington Territory gained from Oregon Territory when Oregon became a state; included parts of present Montana, Idaho, and Wyoming. The newly gained section within present Montana was non-county area. (U.S. Stat., vol. 11, ch. 33 [1859]/pp. 383–384; Van Zandt, 153–155)

SHOSHONE (Idaho) created by Washington Territory from SPOKANE (Wash. Terr., original, extinct) and non-county area; eliminated the non-county area of Washington Territory in present Montana. (Wash. Terr. Laws 1860, 8th sess., pp. 13–14)

WHEATLAND created from MEAGHER and SWEET GRASS. Act passed 22 February 1917; took effect 1 April 1917. (Mont. Laws 1917, 15th leg., ch. 55/pp. 63–70)

WIBAUX created by petition and election from DAWSON and FALLON. WIBAUX overlapped territory claimed by RICHLAND, placing the area in dispute [see 19 February 1915]. (Minutes of Board of County Commissioners, Dawson County, 15 August 1914; Burlingame, 17–19)

Boundary between WIBAUX and RICHLAND was defined, settling boundary dispute dating from 17 August 1914. (Mont. Laws 1915, 14th leg., ch. 24/pp. 32–33)

WIBAUX gained small areas from DAWSON and PRAIRIE when boundary was adjusted to run on federal land survey lines. (Mont. Laws 1917, 15th leg., ch. 139/pp. 232–235)

WIBAUX exchanged with FALLON. (Mont. Laws 1919, 16th leg., ch. 185/pp. 351–352)

YELLOWSTONE created by Montana Territory from CUSTER and GALLATIN; YELLOWSTONE not fully organized, attached to CUSTER "for judicial purposes." (Mont. Terr. Laws 1883, 13th leg., pp. 119–122)

YELLOWSTONE fully organized, detached from CUSTER. (Mont. Terr. Laws 1883, 13th leg., sec. 11/p. 122)

CUSTER lost part of the Crow Indian reservation, which was attached as a non-county area (2) to YELLOWSTONE "for judicial purposes." (Mont. Terr. Laws 1885, 14th leg., p. 74)

YELLOWSTONE boundaries redefined [no change]. (Mont. Terr. Laws 1887, 15th leg., sec. 742/pp. 839–840)

YELLOWSTONE became a county in the state of Montana. (U.S. Stat., vol. 26, pp. 1551–1552 and vol. 25, ch. 180 [1889]/pp. 676–684; Swindler, 6:82–83)

Crow Indians ceded territory to the United States; YELLOWSTONE gained the ceded area. The unceded part of the Crow Indian Reservation west of the Big Horn River remained attached to YELLOWSTONE as a non-county area (2). (Royce, 942–943, pl. 40; U.S. Stat., vol. 26, ch. 543, art. 6, secs. 31–38/pp. 1039–1044)

The Legislature confirmed that the rights of way of the Northern Pacific Railroad and the Rocky Fork and Cooke City Railway within the Crow Indian reservation were attached to YELLOWSTONE "for purposes of taxation and for judicial and other purposes" [see act of 5 March 1885; not mapped]. (Mont. Laws 1891, 2d leg., p. 223)

YELLOWSTONE lost to creation of SWEET GRASS and gained from MEAGHER. (Mont. Laws 1895, 4th leg., pp. 54–58)

YELLOWSTONE lost to creation of CARBON. Act passed 4 March 1895; took effect 1 May 1895. (Mont. Laws 1895, 4th leg., pp. 49–54)

YELLOWSTONE gained all that part of the Crow Indian reservation lying west of the Big Horn River, which had been attached to YELLOWSTONE as non-county area (2). (Mont. Laws 1897, 5th leg., p. 55)

YELLOWSTONE lost to creation of MUSSELSHELL. Act passed 11 February 1911; took effect 1 March 1911. (Mont. Laws 1911, 12th leg., ch. 25/pp. 29–38)

YELLOWSTONE lost to creation of BIG HORN. (Mont. Rev. Code 1921, sec. 4306/pp. 1556–1557; Burlingame, 17–18)

YELLOWSTONE lost to creation of STILLWATER. (Mont. Rev. Code 1921, sec. 4350/pp. 1612–1614; Mont. Laws 1915, 14th leg., ch. 74/pp. 100–102; Burlingame, 17–18)

YELLOWSTONE exchanged with ROSEBUD. (Mont. Laws 1917, 15th leg., ch. 159/pp. 404–405)

YELLOWSTONE exchanged with CARBON. (Mont. Laws 1919, 16th leg., chs. 75, 83/pp. 149–151, 157–158)

YELLOWSTONE lost to CARBON. (Mont. Laws 1925, 19th leg., ch. 30/pp. 34–35)

The United States created America's first national park—Yellowstone. The Park lay mostly in Wyoming Territory, with smaller sections in Montana and Idaho Territories. (U.S. Stat., vol. 17, ch. 24 [1872]/pp. 32–33)

That part of Yellowstone National Park located in Montana was excluded from county jurisdiction and became a non-county area. (Mont. Terr. Laws 1887, 15th leg., pp. 1238–1242)

Boundaries of Yellowstone National Park in Montana were expanded; Yellowstone National Park gained from GALLATIN and PARK. (U.S. Stat., vol. 45, ch. 437 [1929]/pp. 1435–1436; Haines, 2: 325–331)

Boundaries of Yellowstone National Park in Montana were expanded to include an area in PARK known as the "Game Ranch." (Haines, 2: 331–333; U.S. Stat., vol. 44, ch. 399 [1926]/pp. 655–657)

GALLATIN and PARK gained all those parts of Yellowstone National Park located in Montana; Yellowstone National Park eliminated as a non-county area in Montana. (Mont. Laws 1977, 45th leg., ch. 447/pp. 1407–1411; Montana Code Annotated, "Descriptions—County Boundaries," 33)

Montana: Individual County Chronologies