ID: Individual County Chronologies

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

ADA created by Idaho Territory from BOISE. (Id. Terr. Laws 1864, 2nd sess., ch. 29/pp. 430-431)

ADA gained from BOISE and IDAHO. (Id. Terr. Laws 1866, 4th sess., ch. 46/p. 124)

ADA gained from IDAHO. (Id. Terr. Laws 1872, 7th sess., pp. 30-31)

ADA lost to creation of WASHINGTON, and lost to IDAHO. (Id. Terr. Laws 1879, 10th sess., pp. 40-42)

ADA gained from BOISE. (Id. Terr. Laws 1882, 12th sess., pp. 67-68)

ADA boundaries clarified [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 22)

ADA continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

ADA lost to creation of CANYON. Act approved 7 March 1891, became effective through a vote in the general election of 26 November 1892. (Id. Laws 1890, 1st sess., p. 155; Nelson and Webbert, p. 75)

ADA boundary with ELMORE redefined [no change]. (Id. Laws 1895, 3rd sess., pp. 15-16)

ADA boundary with ELMORE redefined [no mappable change]. (Id. Laws 1899, 5th sess., p. 234)

ADA boundary with ELMORE redefined to run along range lines rather than from mouth of Bruneau River to mouth of Mores Creek [no mappable change]. (Id. Laws 1923, 17th sess., ch. 136/pp. 200-202)

ADA lost to ELMORE. Act approved 10 Mar 1947, became effective through a vote in the general election of 2 November 1948. (Id. Laws 1947, 29th sess., ch. 150/pp. 352-359; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-103 "Ada Co."/p. 4)

ADAMS created from WASHINGTON. (Id. Laws 1911, 11th sess., ch. 31/pp. 67-72)

ALTA (extinct) created from ALTURAS (extinct), BOISE, and LOGAN (extinct). ALTURAS and LOGAN eliminated. (Id. Laws 1890, 1st sess., pp. 120-124)

ALTA (extinct) lost to LEHMI. (Id. Laws 1890, 1st sess., p. 166)

ALTA (extinct) lost all territory to ALTURAS (extinct), BOISE, and LOGAN (extinct) when the Idaho Supreme Court declared the act creating ALTA unconstitutional because it failed to provide for an election. ALTA eliminated. (Id. Rpts. 1893, vol. 2/pp. 813-839; Id. Encyclopedia, p. 232)

ALTURAS (extinct) created by Idaho Territory from BOISE. (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 5/pp. 629-630)

ALTURAS (extinct) exchanged with BOISE. (Id. Terr. Laws 1865, 3rd. sess., ch. 56/p. 214)

ALTURAS (extinct) lost to ONEIDA. (Id. Terr. Laws 1876, 9th sess., pp. 90-91)

ALTURAS (extinct) lost to creation of CUSTER, lost small area (along modern BOISE / CUSTER line) to BOISE, and lost to LEMHI. (Id. Terr. Laws 1880, 11th sess., pp. 340-345)

ALTURAS (extinct) lost to BOISE. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 120)

ALTURAS (extinct) boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 76)

ALTURAS (extinct) lost to creation of ELMORE and LOGAN (extinct), and lost to BINGHAM. (Id. Terr. Laws 1888, 15th sess., pp. 33-36)

ALTURAS (extinct) continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

ALTURAS (extinct) lost all territory to creation of ALTA (extinct); ALTURAS eliminated. (Id. Laws 1890, 1st sess., pp. 120-124)

ALTURAS (extinct) restored, with slightly different boundaries, when the Idaho Supreme Court declared the act creating ALTA (extinct) and LINCOLN (original, extinct) unconstitutional because it failed to provide for an election. ALTA eliminated. (Id. Rpts. 1893, vol. 2/pp. 813-839; Id. Encyclopedia, p. 232)

ALTURAS (extinct) lost all territory to creation of BLAINE; ALTURAS eliminated. (Id. Laws 1895, 3rd sess., pp. 31-34)

Legislature authorized BANNOCK to annex territory from CARIBOU, dependent on a vote in the general election of November 1920; proposed annexation failed in referendum [no change]. (Id. Laws 1919, 15th sess., ch. 5/pp. 28-42; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-117 "Caribou Co."/p. 24)

Legislature authorized VALLEY to annex territory from IDAHO, dependent on a vote in the general election of November 1920. No evidence this vote ever took place [no change]. (Id. Laws 1919, 15th sess., ch. 101/pp. 366-367; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-145 "Valley Co."/pp. 56-57)

Legislature authorized BUTTE to annex territory from CUSTER, dependent on a vote in the general election of November 1932. No evidence this vote ever took place [no change]. (Id. Laws 1931, 21st sess., ch. 63/pp. 106-113; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-114 "Butte Co."/p. 21)

Legislature authorized FRANKLIN to annex territory from BANNOCK, dependent on a vote in the general election of November 1932. Proposed annexation failed in referendum [no change]. (Id. Laws 1931, 21st sess., ch. 63/pp. 106-113; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co.", sec. 31-123 "Franklin Co."/pp. 8, 33)

Legislature authorized FRANKLIN to annex territory from BANNOCK, dependent on a vote in the general election of November 1948. Proposed annexation failed in referendum [no change]. (Id. Laws 1947, 29th sess., ch. 255/pp. 699-706; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/p. 8)

Legislature authorized BENEWAH to annex territory from KOOTENAI, dependent on a vote in the general election of November 1950. The election was never held and a writ of mandate was refused by the district court [no change]. (Id. Laws 1949, 30th sess., ch. 92/pp. 162-168; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-197 "Benewah Co."/p. 13)

BANNOCK created from BINGHAM. (Id. Laws 1893, 2nd sess., pp. 170-174)

BANNOCK lost to FRANKLIN. Act approved 8 February 1917, became effective through a vote in the general election of 6 November. (Id. Laws 1917, 14th sess., ch. 96/pp. 327-329; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-123 "Franklin Co."/p. 33)

BANNOCK lost to creation of CARIBOU. Same act also authorized BANNOCK to annex territory from CARIBOU [Annexation 1 (proposed)], dependent on a vote in the general election of November 1920; proposed annexation failed in referendum [no change]. (Id. Laws 1919, 15th sess., ch. 5/pp. 28-42; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-117 "Caribou Co."/p. 24)

BANNOCK gained from ONEIDA; exchanged with POWER. (Id. Laws 1927, 19th sess., ch. 256/pp. 431-439)

Legislature authorized FRANKLIN to annex territory from BANNOCK [Annexation 4 (proposed)], dependent on a vote in the general election of November 1932. Proposed annexation failed in referendum [no change]. (Id. Laws 1931, 21st sess., ch. 63/pp. 106-113; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/p. 8)

BANNOCK lost to FRANKLIN. Act approved 14 March 1945, became effective through a vote in the general election of 5 November 1946. (Id. Laws 1945, 28th sess., ch. 145/pp. 216-224; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/pp. 9-10)

Legislature authorized FRANKLIN to annex territory from BANNOCK [Annexation 5 (proposed)], dependent on a vote in the general election of November 1948. Proposed annexation failed in referendum [no change]. (Id. Laws 1947, 29th sess., ch. 255/pp. 699-706; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/p. 8)

BANNOCK lost to CARIBOU. Areas of loss described in two separate acts approved 18 Mar 1947, became effective through a vote in the general election of 2 November 1948. (Id. Laws 1947, 29th sess., ch. 247/pp. 638-648; ch. 248/pp. 648-657; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/pp. 9-10)

BEAR LAKE created by Idaho Territory from ONEIDA. (Id. Terr. Laws 1874-1875, comp., rev., 8th sess., pp. 720-722)

BEAR LAKE boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 113)

BEAR LAKE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

BEAVERHEAD (Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 3/p. 675)

BEAVERHEAD became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

BENEWAH created from KOOTENAI. (Id. Laws 1915, 13th sess., ch. 4/pp. 5-8)

Legislature authorized BENEWAH to annex territory from KOOTENAI [Annexation 6 (proposed)], dependent on a vote in the general election of November 1950. The election was never held and a writ of mandate was refused by the district court [no change]. (Id. Laws 1949, 30th sess., ch. 92/pp. 162-168; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-197 "Benewah Co."/p. 13)

BIG HORN (Mont., orig., now CUSTER, Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 8/pp. 676-677)

BIG HORN (Mont., orig., now CUSTER, Mont.) became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

BINGHAM created by Idaho Territory from ONEIDA. (Id. Terr. Laws 1884, 13th sess., pp. 41-43)

BINGHAM boundary with LEMHI clarified [no change]. (Id. Terr. Laws 1884, 13th sess., p. 46)

BINGHAM boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 114)

BINGHAM gained from ALTURAS (extinct). (Id. Terr. Laws 1888, 15th sess., pp. 33-36)

BINGHAM continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

BINGHAM lost to LEMHI. (Id. Laws 1890, 1st sess., p. 166)

BINGHAM lost to creation of FREMONT. (Id. Laws 1893, 2nd sess., pp. 94-97)

BINGHAM lost to creation of BANNOCK. (Id. Laws 1893, 2nd sess., pp. 170-174)

BINGHAM lost to FREMONT. Act approved 6 Mar 1903, became effective through a vote in the general election of 8 November 1904. (Id. Laws 1903, 7th sess., pp. 222-223; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

BINGHAM lost to creation of BONNEVILLE. (Id. Laws 1911, 11th sess., ch. 5/pp. 8-9)

BINGHAM lost to creation of POWER. (Id. Laws 1913, 12th sess., ch. 6/pp. 30-45)

BINGHAM lost to creation of BUTTE. (Id. Laws 1917, 14th sess., ch. 98/pp. 344-360)

BINGHAM boundaries redefined [no change]. (Id. Laws 1921, 16th sess., ch. 210/pp. 420-423)

BLAINE created from ALTURAS (extinct) and LOGAN (extinct); ALTURAS and LOGAN eliminated. (Id. Laws 1895, 3rd sess., pp. 31-34)

Legislature authorized CUSTER to annex territory from BLAINE, dependent on a vote in the general election of 1896. No evidence that the vote ever took place; cannot be mapped as described; proposed annexation failed [no change]. (Id. Laws 1895, 3rd sess., pp.140-142; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-121 "Custer Co."/p. 31)

BLAINE lost to creation of LINCOLN. (Id. Laws 1895, 3rd sess., pp. 170-174)

Legislature authorized CUSTER to annex territory from BLAINE, dependent on a vote in the general election of 1900. Proposed annexation failed in referendum; cannot be mapped as described [no change]. (Id. Laws 1899, 5th sess., p. 271; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-109 "Blaine Co."/p. 16)

BLAINE lost to ELMORE. (Id. Laws 1911, 11th sess., ch. 148/pp. 453-454)

BLAINE lost to creation of POWER. (Id. Laws 1913, 12th sess., ch. 6/pp. 30-45)

BLAINE lost to creation of BUTTE and CAMAS. (Id. Laws 1917, 14th sess., ch. 98/pp. 329-360; ch. 97/pp. 329-344)

BLAINE boundaries redefined [no change]. (Id. Laws 1921, 16th sess., ch. 210/pp. 420-423)

BLAINE exchanged with CUSTER. (Id. Laws 1925, 18th sess., ch. 189/pp. 345-348)

BOISE created by Washington Territory from IDAHO; included parts of present Idaho and Wyoming. (Wash. Terr. Laws 1862, 10th sess., pp. 3-4)

BOISE became an Idaho Territory county when the United States created Idaho Territory from Dakota, Nebraska, and Washington Territories. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

BOISE lost to creation of OWYHEE. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 624)

BOISE lost to creation of ONEIDA. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 625)

BOISE exchanged with IDAHO; lost to creation of ALTURAS (extinct). (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 4/p. 629)

BOISE lost to creation of ADA. (Id. Terr. Laws 1864, 2nd sess., ch. 29/pp. 430-431)

BOISE exchanged with ALTURAS (extinct). (Id. Terr. Laws 1865, 3rd. sess., ch. 56/p. 214)

BOISE lost to ADA. (Id. Terr. Laws 1866, 4th sess., ch. 46/p. 124)

BOISE gained from IDAHO [northern boundary of BOISE is an estimated line]. (Id. Terr. Laws 1872, 7th sess., pp. 64-65)

BOISE lost to creation of WASHINGTON. (Id. Terr. Laws 1879, 10th sess., pp. 40-42)

BOISE gained a small area (along modern BOISE / CUSTER line) from ALTURAS (extinct), lost to creation of CUSTER. (Id. Terr. Laws 1880, 11th sess., pp. 340-345)

BOISE lost to ADA and WASHINGTON. (Id. Terr. Laws 1882, 12th sess., pp. 67-68)

BOISE lost to IDAHO. (Id. Terr. Laws 1884, 13th sess., p. 126)

BOISE gained from ALTURAS (extinct), and exchanged with IDAHO. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 120)

BOISE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

BOISE lost to creation of ALTA (extinct). (Id. Laws 1890, 1st sess., pp. 120-124)

BOISE gained from ALTA (extinct) when the Idaho Supreme Court declared the act creating ALTA unconstitutional because it failed to provide for an election. (Id. Rpts. 1893, vol. 2/pp. 813-839; Id. Encyclopedia, p. 232)

BOISE lost to creation of GEM. Act approved 19 March 1915, became effective through a vote in the general election of 11 May 1915. (Id. Laws 1915, 13th sess., ch. 165/pp. 362-375; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-125 "Gem Co."/p. 35)

BOISE lost to creation of VALLEY. Act approved 26 Feb 1917, became effective through a vote in the general election of November 1918. (Id. Laws 1917, 14th sess., ch. 99/pp. 360-372)

BONNER created from KOOTENAI and small remnant of Non-County Area 1. BONNER definition also settled Overlap Area 1 (see 22 December 1864) in favor of SHOSHONE. Non-County Area 1 and Overlap Area 1 eliminated. (Id. Laws 1907, 9th sess., pp. 47-49)

BONNER lost to creation of BOUNDARY. (Id. Laws 1915, 13th sess., ch. 7/pp. 21-29)

BONNEVILLE created from BINGHAM. (Id. Laws 1911, 11th sess., ch. 5/pp. 8-9)

BOUNDARY created from BONNER. (Id. Laws 1915, 13th sess., ch. 7/pp. 21-29)

BUTTE created from BINGHAM, BLAINE, and JEFFERSON. (Id. Laws 1917, 14th sess., ch. 98/pp. 344-360)

BUTTE boundaries clarified[no change]. (Id. Laws 1921, 16th sess., ch. 204/pp. 411-413)

BUTTE gained from CUSTER. (Id. Laws 1937, 21st sess., ch. 138/pp. 222-224)

CAMAS created from BLAINE. (Id. Laws 1917, 14th sess., ch. 97/pp. 329-344)

CAMAS boundaries clarified [no change]. (Id. Laws 1985, 48th leg., 1st. reg. sess., ch. 112/pp. 218-219)

CANYON created from ADA. Act approved 7 March 1891, became effective through a vote in the general election of 26 November 1892. (Id. Laws 1890, 1st sess., p. 155; Nelson and Webbert, p. 75)

CANYON lost to creation of GEM. Act approved 19 March 1915, became effective through a vote in the general election of 11 May 1915. (Id. Laws 1915, 13th sess., ch. 165/pp. 362-375; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-125 "Gem Co."/p. 35)

CANYON lost to creation of PAYETTE. Act approved 28 February 1917, became effective through a vote in a special election of 11 May 1917. (Id. Laws 1917, 14th sess., ch.11/pp. 13-27; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-116 "Canyon Co."/p. 23)

CARIBOU created from BANNOCK. Same act also authorized BANNOCK to annex territory from CARIBOU [Annexation 1 (proposed)], dependent on a vote in the general election of November 1920; proposed annexation failed in referendum [no change]. (Id. Laws 1919, 15th sess., ch. 5/pp. 28-42; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-117 "Caribou Co."/p. 24)

CARIBOU gained from BANNOCK. Areas of gain described in two separate acts approved 18 Mar 1947, became effective through a vote in the general election of 2 November 1948. (Id. Laws 1947, 29th sess., ch. 247/pp. 638-648; ch. 248/pp. 648-657; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/pp. 9-10)

CASSIA created by Idaho Territory from ONEIDA and OWYHEE. (Id. Terr. Laws 1879, 10th sess., pp. 43-46)

Eastern line of CASSIA clarified [no change]. (Id. Terr. Laws 1880, 11th sess., p. 339)

CASSIA boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 125)

CASSIA continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

CASSIA lost to creation of TWIN FALLS. (Id. Laws 1907, 9th sess., pp. 40-41)

CASSIA lost to creation of POWER. (Id. Laws 1913, 12th sess., ch. 6/pp. 30-45)

CHOTEAU (now CHOUTEAU, Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 6/p. 676)

CHOTEAU (now CHOUTEAU, Mont.) became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

CLACKAMAS DISTRICT (Ore.) created as one of four original Oregon counties; included parts of present Oregon, Washington, Idaho, Montana and Canada. (Oregon Archives, p. 26)

CLACKAMAS DISTRICT (Ore.) lost to creation of non-county area in Oregon Country when CLACKAMAS boundary was redefined to run along the Columbia River. Portion of CLACKAMAS in present Idaho was unchanged. (Ore. Terr. Laws 1843-1849, gen. and loc., p. 74)

CLACKAMAS DISTRICT (Ore.) gained from CHAMPOEG DISTRICT (now MARION, Ore.). (Ore. Terr. Laws 1843-1849, gen. and loc., pp. 35-37)

CLACKAMAS DISTRICT (Ore.) renamed CLACKAMAS County [no change]. (Ore. Terr. Laws 1843-1849, gen. and loc., p. 35)

CLACKAMAS (Ore.) lost to British North America when the Oregon Boundary Treaty between the United States and Great Britain established the northern boundary of Oregon Territory at 49 degrees north latitude. (Hayes, 134, 171-174; Parry 100:40-42; Van Zandt, 18)

CLACKAMAS (Ore.) lost to creation of non-county area in Washington Territory. (Van Zandt, 155)

CLACKAMAS (Ore.) lost to creation of WASCO (Ore.); eliminated from present Idaho. (Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27)

Legislature authorized creation of CLARK (proposed) from KOOTENAI. Proposal failed on 12 May 1905 when the Idaho Supreme Court declared the act unconstitutional [no change]. (Id. Laws 1905, 8th sess., pp. 76-82; Id. Rpts. 1907, vol. 11/pp. 14-44)

CLARK created from FREMONT. (Id. Laws 1919, 15th sess., ch. 3/pp. 4-6)

CLARK boundaries redefined [no change]. (Id. Laws 1921, 16th sess., ch. 194/pp. 395-397)

Legislature authorized creation of CLEARWATER (proposed) from NEZ PERCE and SHOSHONE. Proposal failed on 14 June 1901 when the Idaho Supreme Court ruled the act invalid [no change]. (Id. Laws 1901, 6th sess., pp. 209-210; Id. Rpts. 1903, vol. 7/pp. 752-762; ISHS Ref. Series #334)

CLEARWATER created from NEZ PERCE. (Id. Laws 1911, 11th sess., ch. 24/pp. 49-60)

CUSTER created by Idaho Territory from ALTURAS (extinct), BOISE, and LEMHI. (Id. Terr. Laws 1880, 11th sess., pp. 340-345)

CUSTER boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., pp. 128-129)

CUSTER gained from IDAHO. (Id. Terr. Laws 1888, 15th sess., pp. 22-23)

CUSTER continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

Legislature authorized CUSTER to annex territory from BLAINE, dependent on a vote in the general election of 1896. No evidence that the vote ever took place; proposed annexation failed; cannot be mapped as described [no change]. (Id. Laws 1895, 3rd sess., pp.140-142; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-121 "Custer Co."/p. 31)

CUSTER exchanged with BLAINE. (Id. Laws 1925, 18th sess., ch. 189/pp. 345-348)

Legislature authorized BUTTE to annex territory from CUSTER [Annexation 3 (proposed)], dependent on a vote in the general election of November 1932. No evidence this vote ever took place [no change]. (Id. Laws 1931, 21st sess., ch. 63/pp. 106-113; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-114 "Butte Co."/p. 21)

CUSTER lost to BUTTE. (Id. Laws 1937, 21st sess., ch. 138/pp. 222-224)

DAWSON (Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 7/p. 676)

DAWSON (Mont.) became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

DEER LODGE (Mont.) created by Idaho Territory from IDAHO, MISSOULA (Mont.), and Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 2/pp. 674-675)

DEER LODGE (Mont.) became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

ELMORE created by Idaho Territory from ALTURAS (extinct). (Id. Terr. Laws 1888, 15th sess., pp. 33-36)

ELMORE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

ELMORE boundary with ADA clarified [no change]. (Id. Laws 1895, 3rd sess., pp. 15-16)

ELMORE boundary with ADA redefined [no mappable change]. (Id. Laws 1899, 5th sess., p. 234)

ELMORE gained from BLAINE. (Id. Laws 1911, 11th sess., ch. 148/pp. 453-454)

ELMORE redefined [no change]. (Id. Laws 1919, 15th sess., ch. 109/pp. 391-392)

ELMORE boundary with ADA redefined to run along range lines rather than from mouth of Bruneau River to mouth of Mores Creek [no mappable change]. (Id. Laws 1923, 17th sess., ch. 136/pp. 200-202)

ELMORE redefined [no change]. (Id. Laws 1925, 18th sess., ch. 26/pp. 38-39)

ELMORE gained from OWYHEE. Act approved 21 Feb 1929, became effective through a vote in the general election of 4 November 1930. (Id. Laws 1929, 20th sess., ch. 47/pp. 59-66; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-122 "Elmore Co."/p.32)

ELMORE gained from ADA. Act approved 10 Mar 1947, became effective through a vote in the general election of 2 November 1948. (Id. Laws 1947, 29th sess., ch. 150/pp. 352-359; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-103 "Ada Co."/p. 4)

FRANKLIN created from ONEIDA. (Id. Laws 1913, 12th sess., ch. 5/pp. 22-30)

FRANKLIN gained from BANNOCK. Act approved 8 Feb 1917, became effective through a vote in the general election of 6 November. (Id. Laws 1917, 14th sess., ch. 96/pp. 327-329; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-123 "Franklin Co."/p. 33)

FRANKLIN gained from BANNOCK. Act approved 14 March 1945, became effective through a vote in the general election of 5 November 1946. (Id. Laws 1945, 28th sess., ch. 145/pp. 216-224; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-105 "Bannock Co."/pp. 9-10)

FREMONT created from BINGHAM. (Id. Laws 1893, 2nd sess., pp. 94-97)

FREMONT gained from LEMHI. Act approved 11 March 1895, became effective through a vote in the general election of 3 November 1896. (Id. Laws 1895, 3rd sess., pp. 145-148; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

The State of Idaho ceded to the United States jurisdiction over "all such lands within the State as may be included in the territory of the Yellowstone National Park. . . .," did not change the boundaries of FREMONT, the only Idaho county which includes a portion of Yellowstone National Park. (Id. Laws 1899, 5th sess., p. 22)

FREMONT's gain from LEMHI on 3 November 1896 was reenacted [no change]. (Id. Laws 1899, 5th sess., pp. 273-275; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

FREMONT gained from BINGHAM. Act approved 6 Mar 1903, became effective through a vote in the general election of 8 November 1904. (Id. Laws 1903, 7th sess., pp. 222-223; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

FREMONT lost to creation of JEFFERSON and MADISON. Acts approved 18 February 1913, became effective through a vote in the general election of 4 November 1913. (Id. Laws 1913, 12th sess., ch. 25/pp. 94-107; ch. 26/pp. 107-121; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-128 "Jefferson Co.", sec. 31-135 "Madison Co."/pp. 38, 46)

FREMONT lost to creation of CLARK. (Id. Laws 1919, 15th sess., ch. 3/pp. 4-6)

GEM created from BOISE and CANYON. Act approved 19 March 1915, became effective through a vote in the general election of 11 May 1915. (Id. Laws 1915, 13th sess., ch. 165/pp. 362-375; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-125 "Gem Co."/p. 35)

GOODING created from LINCOLN. (Id. Laws 1913, 12th sess., ch. 4/pp. 13-21)

GOODING lost to creation of JEROME. (Id. Laws 1919, 15th sess., ch. 4/pp. 14-28)

IDAHO created by Washington Territory from SHOSHONE; included parts of present Idaho, Montana, and Wyoming. (Wash. Terr. Laws 1861-1862, 9th sess., p. 3)

IDAHO lost to creation of BOISE. (Wash. Terr. Laws 1862, 10th sess., pp. 3-4)

IDAHO became an Idaho Territory county when the United States created Idaho Territory from Dakota, Nebraska, and Washington Territories. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

IDAHO lost to creation of DEER LODGE (Mont.), and lost to MISSOULA (Mont.). (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 1/p. 674)

IDAHO exchanged with BOISE, lost to NEZ PERCE. (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 3/p. 629)

IDAHO lost to NEZ PERCE [estimated line]. (Id. Terr. Laws 1865, 3rd. sess., ch. 38/pp. 182-183)

IDAHO gained from NEZ PERCE. (Id. Terr. Laws 1866, 4th sess., ch. 48/p. 126)

IDAHO lost to ADA. (Id. Terr. Laws 1866, 4th sess., ch. 46/p. 124)

IDAHO lost to creation of LEMHI. (Id. Terr. Laws 1868, 5th sess., ch. 19/pp. 117-118)

IDAHO lost to ADA, BOISE, and LEMHI [boundary with BOISE is an estimated line]. (Id. Terr. Laws 1872, 7th sess., pp. 30-31; 47-48; 64-65)

IDAHO gained from NEZ PERCE [a portion of this line is estimated]. (Id. Terr. Laws 1874-1875, comp., rev., 8th sess., pp. 730-732)

IDAHO gained from ADA. (Id. Terr. Laws 1879, 10th sess., pp. 40-42)

IDAHO gained from BOISE, LEMHI, and NEZ PERCE. (Id. Terr. Laws 1884, 13th sess., p. 126)

IDAHO exchanged with BOISE. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 120)

IDAHO boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 133)

IDAHO lost to CUSTER. (Id. Terr. Laws 1888, 15th sess., pp. 22-23)

IDAHO exchanged with NEZ PERCE. (Id. Terr. Laws 1888, 15th sess., pp. 50-51)

IDAHO continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

IDAHO exchanged with WASHINGTON. (Id. Laws 1890, 1st sess., pp. 41-42)

IDAHO northern boundary clarified [no change]. (Id. Laws 1890, 1st sess., pp. 117-118)

IDAHO lost to WASHINGTON. (Id. Laws 1895, 3rd sess., pp. 21-22)

IDAHO redefined [no change]. (Id. Laws 1899, 5th sess., pp. 79-80)

IDAHO lost to LEMHI when line between the two counties was redefined. Faulty geographic knowledge also created an overlap between IDAHO and LEMHI (see Overlap Area 2). (Id. Laws 1903, 7th sess., pp. 48-49)

IDAHO lost to LEMHI. Overlap between IDAHO and LEMHI (see 21 February 1903) settled in favor of IDAHO; Overlap Area 2 eliminated. (Id. Laws 1911, 11th sess., ch. 218/pp. 699-701)

Legislature authorized the creation of SELWAY (proposed) from IDAHO and LEWIS, dependent on a vote in a special election held 2 July 1917. Proposal failed in referendum [no change]. (Id. Laws 1917, 14th sess., ch. 127/pp. 418-430; www.researchnetwork.net)

IDAHO lost to creation of VALLEY. Act approved 26 February 1917, became effective through a vote in the general election of 6 November 1918. (Id. Laws 1917, 14th sess., ch. 99/pp. 360-372)

Legislature authorized VALLEY to annex territory from IDAHO [Annexation 2 (proposed)], dependent on a vote in the general election of November 1920. No evidence this vote ever took place [no change]. (Id. Laws 1919, 15th sess., ch. 101/pp. 366-367; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-145 "Valley Co."/pp. 56-57)

JEFFERSON (Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 5/pp. 675-676)

JEFFERSON (Mont.) became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

JEFFERSON created from FREMONT. Act approved 18 February 1913, became effective through a vote in the general election of 4 November 1913. (Id. Laws 1913, 12th sess., ch. 25/pp. 94-107; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-128 "Jefferson Co."/pp. 38; Nelson and Webbert, p. 88)

JEFFERSON lost to creation of BUTTE. (Id. Laws 1917, 14th sess., ch. 98/pp. 344-360)

JEROME created from GOODING, LINCOLN, and MINIDOKA. (Id. Laws 1919, 15th sess., ch. 4/pp. 14-28)

KOOTENAI created by Idaho Territory from Non-County Area 1. Faulty geographic knowledge in KOOTENAI description resulted in an overlap with SHOSHONE (see Overlap Area 1). KOOTENAI attached to NEZ PERCE "for all civil and criminal jurisprudence". (Id. Terr. Laws 1864, 2nd sess., ch. 30/pp. 432-433)

KOOTENAI gained from LAH-TOH (extinct); LAH-TOH eliminated. (Id. Terr. Laws 1866, 4th sess., ch. 48/p. 126)

KOOTENAI boundaries redefined, overlap with SHOSHONE continued [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 142)

KOOTENAI continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

KOOTENAI boundary with LATAH redefined [no change]. (Id. Laws 1905, 8th sess., pp. 333-334)

Legislature authorized creation of CLARK (proposed) and LEWIS (proposed) from KOOTENAI. Proposal failed on 12 May 1905 when the Idaho Supreme Court declared the act unconstitutional [no change]. (Id. Laws 1905, 8th sess., pp. 76-82; Id. Rpts. 1907, vol. 11/pp. 14-44)

KOOTENAI lost to creation of BONNER. Overlap between KOOTENAI and SHOSHONE settled in favor of SHOSHONE; Overlap Area 1 eliminated. (Id. Laws 1907, 9th sess., pp. 47-49)

KOOTENAI boundaries redefined [no change]. (Id. Laws 1909, 10th sess., pp. 318-319)

KOOTENAI lost to creation of BENEWAH. (Id. Laws 1915, 13th sess., ch. 4/pp. 5-8)

LAH-TOH (Idaho Terr., extinct) created by Idaho Territory from Non-County Area 1. LAH-TOH attached to NEZ PERCE "for all civil and criminal jurisprudence". (Id. Terr. Laws 1864, 2nd sess., ch. 30/pp. 432-433)

LAH-TOH (Idaho Terr., extinct) lost all territory to KOOTENAI and NEZ PERCE; LAH-TOH eliminated. (Id. Terr. Laws 1866, 4th sess., ch. 48/p. 126)

LANE (Ore.) created from non-county area in Oregon Territory; included parts of present Idaho and Wyoming. (Ore. Terr. Laws 1850, 2nd sess., pp. 32-33)

LANE (Ore.) lost small area to creation of DOUGLAS (Ore.); portion of LANE in present Idaho unchanged. (Ore. Terr. Laws 1851, 3rd reg. sess., p. 18)

LANE (Ore.) gained from UMPQUA (Ore., extinct), gained from non-county area in Oregon Territory, and exchanged with DOUGLAS (Ore.). Portion of LANE in present Idaho was unchanged. (Ore. Terr. Special Laws, 1853, 5th reg. sess., p. 13)

LANE (Ore.) lost to creation of WASCO (Ore.); eliminated from present Idaho and Wyoming. (Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27)

LATAH created by the United States Congress from NEZ PERCE. (U.S. Stat., vol. 25, ch. 251 [1888]/pp. 147-149; Id. Encyclopedia, pp. 297-298)

LATAH boundary with KOOTENAI redefined [no change]. (Id. Laws 1905, 8th sess., pp. 333-334)

LATAH boundaries redefined [no change]. (Id. Laws 1909, 10th sess., p. 319)

LATAH boundaries clarified [no change]. (Id. Laws 1978, 44th leg., 2d reg. sess., ch. 248/pp. 543-545)

LEMHI created by Idaho Territory from IDAHO. (Id. Terr. Laws 1868, 5th sess., ch. 19/pp. 117-118)

LEMHI gained from IDAHO. (Id. Terr. Laws 1872, 7th sess., pp. 47-48)

LEMHI lost to ONEIDA. (Id. Terr. Laws 1876, 9th sess., pp. 90-91)

LEMHI gained from ALTURAS (extinct), lost to creation of CUSTER. (Id. Terr. Laws 1880, 11th sess., pp. 340-345)

LEMHI lost to IDAHO. (Id. Terr. Laws 1884, 13th sess., p. 126)

LEMHI boundary with BINGHAM clarified [no change]. (Id. Terr. Laws 1884, 13th sess., p. 46)

LEMHI boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 144)

LEMHI continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

LEMHI gained from ALTA (extinct) and BINGHAM. (Id. Laws 1890, 1st sess., p. 166)

LEMHI lost to FREMONT. Act approved 11 March 1895, became effective through a vote in the general election of 3 November 1896. (Id. Laws 1895, 3rd sess., pp. 145-148; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

LEMHI redefined [no change]. (Id. Laws 1899, 5th sess., p. 111)

LEMHI's loss to FREMONT on 3 November 1896 was reenacted [no change]. (Id. Laws 1899, 5th sess., pp. 273-275; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-124 "Fremont Co."/p. 35)

LEMHI gained from IDAHO when line between the two counties was redefined. Faulty geographic knowledge also created an overlap between IDAHO and LEMHI (see Overlap Area 2). (Id. Laws 1903, 7th sess., pp. 48-49)

LEMHI gained from IDAHO. Overlap between IDAHO and LEMHI (see 21 February 1903) settled in favor of IDAHO; Overlap Area 2 eliminated. (Id. Laws 1911, 11th sess., ch. 218/pp. 699-701)

Legislature authorized creation of LEWIS (proposed) from KOOTENAI. Proposal failed on 12 May 1905 when the Idaho Supreme Court declared the act unconstitutional [no change]. (Id. Laws 1905, 8th sess., pp. 76-82; Id. Rpts. 1907, vol. 11/pp. 14-44)

LEWIS created from NEZ PERCE. (Id. Laws 1911, 11th sess., ch. 37/pp. 77-84)

LINCOLN (original, extinct) created from LOGAN (extinct). LOGAN eliminated. (Id. Laws 1890, 1st sess., pp. 120-124)

LINCOLN (original, extinct) lost all territory to LOGAN (extinct) when the Idaho Supreme Court declared the act creating LINCOLN unconstitutional because it failed to provide for an election. LINCOLN (original) eliminated. (Id. Rpts. 1893, vol. 2/pp. 813-839; Id. Encyclopedia, p. 232)

LINCOLN created from BLAINE. (Id. Laws 1895, 3rd sess., pp. 170-174)

LINCOLN lost to creation of GOODING and MINIDOKA. (Id. Laws 1913, 12th sess., ch. 3/pp. 5-13; ch. 4/pp. 13-21)

LINCOLN lost to creation of JEROME. (Id. Laws 1919, 15th sess., ch. 4/pp. 14-28)

LINN (Ore.) created by the Provisional Legislature of Oregon Territory from CHAMPOEG (now MARION, Ore.). (Ore. Terr. Laws 1843-1849, gen. and loc., pp. 55-56)

LINN (Ore.) lost to creation of non-county area in Oregon Territory when the county's southern line redefined. LINN continued to include territory in present Idaho and Wyoming. (Ore. Terr. Laws 1850, 2nd sess., pp. 33-34)

LINN (Ore.) lost to creation of WASCO (Ore.); eliminated from present Idaho and Wyoming. (Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27)

LOGAN (extinct) created by Idaho Territory from ALTURAS (extinct). (Id. Terr. Laws 1888, 15th sess., pp. 33-36)

LOGAN (extinct) continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

LOGAN (extinct) lost all territory to creation of ALTA (extinct) and LINCOLN (original, extinct); ALTA and LOGAN eliminated. (Id. Laws 1890, 1st sess., pp. 120-124)

LOGAN (extinct) restored when the Idaho Supreme Court declared the act creating ALTA (extinct) and LINCOLN (original, extinct) unconstitutional because it failed to provide for an election. ALTA and LINCOLN eliminated. (Id. Rpts. 1893, vol. 2/pp. 813-839; Id. Encyclopedia, p. 232)

LOGAN (extinct) lost all territory to creation of BLAINE; LOGAN eliminated. (Id. Laws 1895, 3rd sess., pp. 31-34)

MADISON (Mont.) created by Idaho Territory from Non-County Area 2. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 4/p. 675)

MADISON became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

MADISON created from FREMONT. Act approved 18 February 1913, became effective through a vote in the general election of 4 November 1913. (Id. Laws 1913, 12th sess., ch. 26/pp. 107-121; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-135 "Madison Co."/pp. 46; Nelson and Webbert, p. 100)

MADISON lost to creation of TETON. (Id. Laws 1915, 13th sess., ch. 28/pp. 29-30)

CHAMPOEG DISTRICT (now MARION, Ore.) created as one of four original Oregon counties; included parts of present Oregon, Washington, Idaho, and Montana. (Oregon Archives, p. 26)

CHAMPOEG DISTRICT (now MARION, Ore.) lost to CLACKAMAS DISTRICT (Ore.). (Ore. Terr. Laws 1843-1849, gen. and loc., pp. 35-37)

CHAMPOEG DISTRICT (now MARION, Ore.) renamed CHAMPOEG County; no change in boundaries [not mapped]. (Ore. Terr. Laws 1843-1849, gen. and loc., p. 35)

CHAMPOEG (now MARION, Ore.) lost to creation of LINN (Ore.). (Ore. Terr. Laws 1843-1849, gen. and loc., pp. 55-56)

CHAMPOEG (Ore.) renamed MARION (Ore.). (Ore. Terr. Laws 1850, 2nd sess., p. 53)

MARION (Ore.) lost to creation of WASCO (Ore.); eliminated from Idaho. (Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27)

MINIDOKA created from LINCOLN. (Id. Laws 1913, 12th sess., ch. 3/pp. 5-13)

MINIDOKA lost to creation of JEROME. (Id. Laws 1919, 15th sess., ch. 4/pp. 14-28)

MISSOULA (Mont.) 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 (Mont.) lost to creation of NEZ PERCE, and lost to SHOSHONE. (Wash. Terr. Laws 1861-1862, 9th sess., pp. 4-5)

MISSOULA (Mont.) became an Idaho Territory county when the United States created Idaho Territory from Dakota, Nebraska, and Washington Territories. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

MISSOULA (Mont.) gained from IDAHO, Non-County Area 1 and Non-County Area 2; lost to creation of DEER LODGE (Mont.). (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 1/p. 674)

MISSOULA became a Montana Territory county; eliminated from Idaho Territory. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 1/pp. 85-92; Sanders, Helen F., 1:329; Van Zandt, 145)

NEZ PERCE created by Washington Territory from MISSOULA (Mont.), SHOSHONE and SPOKANE (Wash. Terr., original, extinct). (Wash. Terr. Laws 1861-1862, 9th sess., p. 4)

NEZ PERCE gained from SPOKANE (Wash. Terr., original, extinct). (Wash. Terr. Laws 1862, 10th sess., p. 5)

NEZ PERCE lost to SPOKANE (Wash. Terr., original, extinct) and became an Idaho Territory county when the United States created Idaho Territory from Dakota, Nebraska, and Washington Territories. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

NEZ PERCE gained from IDAHO, lost to Non-County Area 1. Non-County Area 1 attached to NEZ PERCE for "all civil and judicial purposes". (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 1/p. 628)

NEZ PERCE gained from IDAHO [estimated line]. (Id. Terr. Laws 1865, 3rd. sess., ch. 38/pp. 182-183)

NEZ PERCE gained from LAH-TOH (extinct), lost to IDAHO; LAH-TOH eliminated. (Id. Terr. Laws 1866, 4th sess., ch. 48/p. 126)

NEZ PERCE lost to IDAHO [a portion of this line is estimated]. (Id. Terr. Laws 1874-1875, comp., rev., 8th sess., pp. 730-732)

NEZ PERCE lost to IDAHO. (Id. Terr. Laws 1884, 13th sess., p. 126)

NEZ PERCE boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 146)

NEZ PERCE lost to creation of LATAH. (U.S. Stat., vol. 25, ch. 251 [1888]/pp. 147-149; Id. Encyclopedia, pp. 297-298)

NEZ PERCE exchanged with IDAHO. (Id. Terr. Laws 1888, 15th sess., pp. 50-51)

NEZ PERCE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

NEZ PERCE gained from SHOSHONE. Act approved 10 March 1903, became effective through a vote in the general election of 8 November 1904. (Id. Laws 1903, 7th sess., pp. 204-206; Id. Laws 1905, 8th sess., pp. 331-333; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-137 "Nez Perce Co."/p. 49)

NEZ PERCE boundaries redefined [no change]. (Id. Laws 1909, 10th sess., pp. 319-320)

NEZ PERCE lost to creation of CLEARWATER. (Id. Laws 1911, 11th sess., ch. 24/pp. 49-60)

NEZ PERCE lost to creation of LEWIS. (Id. Laws 1911, 11th sess., ch. 37/pp. 77-84)

NEZ PERCE boundaries clarified [no change]. (Id. Laws 1978, 44th leg., 2d reg. sess., ch. 248/pp. 543-545)

Non-County Area 1 created from SPOKANE (Wash. Terr., original, extinct) when the United States defined the boundaries for Idaho Territory. Non-County Area 1 included parts of present Idaho and Montana. (Id. Terr. Laws 1863, loc. and spec., 1st sess., pp. 27-28)

Non-County Area 1 lost to MISSOULA (Mont.). (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 1/p. 674)

Non-County Area 1 gained from NEZ PERCE, lost to SHOSHONE; attached to NEZ PERCE for "all civil and judicial purposes". (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 1/p. 628)

Non-County Area 1 lost almost all territory to creation of KOOTENAI and LAH-TOH (extinct). A tiny remnant of non-county area remained above the northeast corner of SHOSHONE until 21 February 1907. (Id. Terr. Laws 1864, 2nd sess., ch. 30/pp. 432-433)

Small remnant of Non-County Area 1 eliminated by creation of BONNER. (Id. Laws 1907, 9th sess., pp. 47-49)

Non-County Area 2 created from parts of Dakota and Nebraska Territories when the United States defined the boundaries for Idaho Territory. Non-County Area 2 included parts of present Idaho, Montana, and Wyoming. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

Non-County Area 2 lost to creation of OWYHEE. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 624)

Non-County Area 2 lost to creations of BEAVERHEAD (Mont.), BIG HORN (now CUSTER, Mont.), CHOTEAU (now CHOUTEAU, Mont.), DAWSON (Mont.), DEER LODGE (Mont.), JEFFERSON (Mont.), MADISON (Mont.), OGALALA (Idaho Territory, extinct), and YELLOWSTONE (Idaho Territory, extinct). Non-County Area 2 eliminated. (Id. Terr. Laws 1863, loc. and spec., 1st sess., secs. 1-10/pp. 674-677)

OGALALA (Idaho Territory, extinct) created by Idaho Territory from Non-County Area 2. OGALALA was located entirely in the eastern half of present Wyoming. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 9/p. 677)

Dakota Territory gained OGALALA (Id. Terr., extinct) and most of present Wyoming from Idaho Territory; OGALALA eliminated. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 18/p. 92; Van Zandt, 134-136, 156-157)

ONEIDA created by Idaho Territory from BOISE and OWYHEE; included parts of present Idaho and Wyoming. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 625)

ONEIDA lost to Dakota Territory. ONEIDA continued to include part of present Wyoming. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 18/p. 92; Van Zandt, 134-136, 156-157)

ONEIDA lost to creation of Wyoming Territory. (Trenholm, 1:83-84; U.S. Stat., vol. 15, ch. 235 [1868], secs. 1, 17/pp. 178, 183; Van Zandt, 136, 144, 156)

ONEIDA gained from OWYHEE. (Id. Terr. Laws 1870, 6th sess., p. 54)

ONEIDA lost to creation of BEAR LAKE. (Id. Terr. Laws 1874-1875, comp., rev., 8th sess., pp. 720-722)

ONEIDA gained from ALTURAS (extinct) and LEMHI. (Id. Terr. Laws 1876, 9th sess., pp. 90-91)

ONEIDA lost to creation of CASSIA. (Id. Terr. Laws 1879, 10th sess., pp. 43-46)

ONEIDA lost to creation of BINGHAM. (Id. Terr. Laws 1884, 13th sess., pp. 41-43)

ONEIDA boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 191)

ONEIDA continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

ONEIDA lost to creation of FRANKLIN and POWER. (Id. Laws 1913, 12th sess., ch. 5/pp. 22-30; ch. 6/pp. 30-45)

ONEIDA lost to POWER. Act approved 15 March 1915, became effective through a vote in the general election of 7 November 1916. (Id. Laws 1915, 13th sess., ch. 132/pp. 287-289; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-139 "Oneida Co."/p. 50)

ONEIDA lost to BANNOCK. (Id. Laws 1927, 19th sess., ch. 256/pp. 431-439)

Non-county area created in Oregon Territory from LINN (Ore.) when the county's southern line redefined; included parts of present Idaho and Wyoming. (Ore. Terr. Laws 1850, 2nd sess., pp. 33-34)

Non-county area in Oregon Territory lost to creation of LANE (Ore.); non-county area eliminated. (Ore. Terr. Laws 1850, 2nd sess., pp. 32-33)

Overlap Area 1 created between KOOTENAI and SHOSHONE when the boundary definition for the creation of KOOTENAI was based on faulty geographic knowledge. (Id. Terr. Laws 1864, 2nd sess., ch. 30/pp. 432-433)

Overlap Area 1 settled in favor of SHOSHONE when BONNER was created; Overlap Area 1 eliminated. (Id. Laws 1907, 9th sess., pp. 47-49)

Overlap Area 2 was created between IDAHO and LEMHI when a redefinition of their boundary was based on faulty geographic knowledge. Overlap eliminated 10 March 1911. (Id. Laws 1903, 7th sess., pp. 48-49)

Overlap Area 2 settled in favor of IDAHO when LEMHI boundaries redefined. Overlap Area 2 eliminated. (Id. Laws 1911, 11th sess., ch. 218/pp. 699-701)

OWYHEE created by Idaho Territory from BOISE and Non-County Area 2; included parts of present Idaho and Wyoming. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 624)

OWYHEE lost to creation of ONEIDA. (Id. Terr. Laws 1863, loc. and spec., 1st sess., p. 625)

OWYHEE redefined [no change]. (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 6/p. 630)

OYWHEE lost to ONEIDA. (Id. Terr. Laws 1870, 6th sess., p. 54)

OWYHEE lost to creation of CASSIA. (Id. Terr. Laws 1879, 10th sess., pp. 43-46)

OWYHEE boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 195)

OWYHEE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

OWYHEE lost to ELMORE. Act approved 21 Feb 1929, became effective through a vote in the general election of 4 November 1930. (Id. Laws 1929, 20th sess., ch. 47/pp. 59-66; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-122 "Elmore Co."/p.32)

OWYHEE boundaries clarified [no change]. (Id. Laws 1999, 55th leg., 1st reg. sess., ch. 35/pp. 72-73)

PAYETTE created from CANYON. Act approved 28 February 1917, became effective through a vote in the special election of 11 May 1917. (Id. Laws 1917, 14th sess., ch.11/pp. 13-27; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-140 "Payette Co."/p. 52)

POWER created from BINGHAM, BLAINE, CASSIA, and ONEIDA. (Id. Laws 1913, 12th sess., ch. 6/pp. 30-45)

POWER gained from ONEIDA. Act approved 15 March 1915, became effective through a vote in the general election of 7 November 1916. (Id. Laws 1915, 13th sess., ch. 132/pp. 287-289; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-142 "Power Co."/p. 54)

POWER exchanged with BANNOCK. (Id. Laws 1927, 19th sess., ch. 256/pp. 431-439)

Legislature authorized the creation of SELWAY (proposed) from IDAHO and LEWIS, dependent on a vote in the special election of 2 July 1917. Proposal failed in referendum [no change]. (Id. Laws 1917, 14th sess., ch. 127/pp. 418-430; www.researchnetwork.net)

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

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

SHOSHONE gained from MISSOULA (Mont.) and SPOKANE (Wash. Terr., original, extinct), lost to creation of IDAHO, and NEZ PERCE. (Wash. Terr. Laws 1861-1862, 9th sess., pp. 4-5)

SHOSHONE became an Idaho Territory county when the United States created Idaho Territory from Dakota, Nebraska, and Washington Territories. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

SHOSHONE gained from Non-County Area 1. (Id. Terr. Laws 1863, loc. and spec., 1st. sess., sec. 2/p. 629)

Faulty geographic knowledge in the creation of KOOTENAI resulted in an overlap with SHOSHONE (see Overlap Area 1). (Id. Terr. Laws 1864, 2nd sess., ch. 30/pp. 432-433)

SHOSHONE boundaries redefined, overlap with KOOTENAI continued [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 201)

SHOSHONE continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

SHOSHONE lost to NEZ PERCE. Act approved 10 March 1903, became effective through a vote in the general election of 8 November 1904. (Id. Laws 1903, 7th sess., pp. 204-206; Id. Laws 1905, 8th sess., pp. 331-333; Id. Code Ann. (1996), vol. 6, ch. 1, sec. 31-137 "Nez Perce Co."/p. 49)

Overlap between KOOTENAI and SHOSHONE settled in favor of SHOSHONE; Overlap Area 1 eliminated. (Id. Laws 1907, 9th sess., pp. 47-49)

SHOSHONE boundaries redefined [no change]. (Id. Laws 1909, 10th sess., p. 320)

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

SKAMANIA (Wash.) lost to creation of WALLA WALLA (Wash.); eliminated from Idaho. (Wash. Terr. Laws 1854, 1st sess., pp. 472-473)

SPOKANE (Wash. Terr., original, extinct) created by Washington Territory from WALLA WALLA; included parts of present Idaho and Montana. SPOKANE not fully organized, not attached. (Wash. Terr. Laws 1857, 5th reg. sess., p. 51)

SPOKANE (Wash. Terr., original, extinct) redefined and fully organized [no change]. (Wash. Terr. Laws 1859, 7th reg. sess., p. 436)

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

SPOKANE (Wash. Terr., original, extinct) lost to creation of SHOSHONE. (Wash. Terr. Laws 1860, 8th sess., pp. 13-14)

SPOKANE (Wash. Terr., original, extinct) lost to creation of NEZ PERCE, and lost to SHOSHONE. (Wash. Terr. Laws 1861-1862, 9th sess., pp. 4-5)

SPOKANE (Wash. Terr., original, extinct) lost to NEZ PERCE. (Wash. Terr. Laws 1862, 10th sess., p. 5)

SPOKANE (Wash. Terr., orig., extinct) lost to creation of Idaho Territory; eliminated from Idaho. (U.S. Stat., vol. 12, ch. 117 [1863]/pp. 808-814; Van Zandt, 156-158)

TETON created from MADISON. (Id. Laws 1915, 13th sess., ch. 28/pp. 29-30)

TWIN FALLS created from CASSIA. (Id. Laws 1907, 9th sess., pp. 40-41)

VALLEY created from BOISE and IDAHO. Act approved 26 February 1917, became effective through a vote in the general election of November 1918. (Id. Laws 1917, 14th sess., ch. 99/pp. 360-372)

WALLA WALLA (Wash.) created by Washington Territory from SKAMANIA (Wash.) and non-county area in Washington Territory. WALLA WALLA overlapped the eastern end of WHATCOM (Wash) and included parts of present Idaho and Montana. (Wash. Terr. Laws 1854, 1st sess., pp. 472-473)

Overlap between WALLA WALLA and WHATCOM settled in favor of WHATCOM. Portion of WALLA WALLA in present Idaho was unchanged. (Wash. Terr. Laws 1857, 5th reg. sess., p. 53)

WALLA WALLA (Wash.) lost to creation of SPOKANE (Wash. Terr., original, extinct); WALLA WALLA eliminated from present Idaho. (Wash. Terr. Laws 1857, 5th reg. sess., p. 51)

WASCO (Ore.) created by Oregon Territory from CLACKAMAS (Ore.), JACKSON (Ore.), LANE (Ore.), LINN (Ore.), and MARION (Ore.); included parts of present Idaho, Montana, and Wyoming. (Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27)

WASCO (Ore.) lost to creation of non-county area in Washington Territory when Oregon became a state; WASCO eliminated from present Idaho. (Ore. Laws 1860, 1st reg. sess., pp. 28-30; Van Zandt, p. 155)

WASHINGTON created by Idaho Territory from ADA and BOISE. (Id. Terr. Laws 1879, 10th sess., pp. 40-42)

WASHINGTON gained from BOISE. (Id. Terr. Laws 1882, 12th sess., pp. 67-68)

WASHINGTON boundaries redefined [no change]. (Id. Terr. Laws 1887, comp., spec. and loc., 14th sess., p. 205)

WASHINGTON continued as an Idaho county when the state of Idaho admitted to the Union and Idaho Territory eliminated. (U.S. Stat., vol. 26, ch. 656 [1890]/pp. 215-219; Van Zandt, 156)

WASHINGTON exchanged with IDAHO. (Id. Laws 1890, 1st sess., pp. 41-42)

WASHINGTON gained from IDAHO. (Id. Laws 1895, 3rd sess., pp. 21-22)

WASHINGTON redefined [no change]. (Id. Laws 1899, 5th sess., pp. 22-23)

WASHINGTON boundaries redefined [no change]. (Id. Laws 1905, 8th sess., pp. 303-304)

WASHINGTON lost to creation of ADAMS. (Id. Laws 1911, 11th sess., ch. 31/pp. 67-72)

Non-county area created in Washington Territory from CLACKAMAS (Ore.); included most of northern Idaho and part of present Montana. (Wash. Terr. Laws, 1854, 1st. sess., p. 32; Van Zandt, 155)

Non-county area in Washington Territory gained from CLARK (Wash.), lost to creation of SKAMAMIA (Wash.). (Wash. Terr. Laws 1854, 1st sess., p. 473)

Non-county area in Washington Territory lost to creation of WALLA WALLA (Wash.); non-county area eliminated. (Wash. Terr. Laws 1854, 1st sess., pp. 472-473)

Non-county area created in Washington Territory from WASCO (Ore.) when Oregon became a state; included the southern half of Idaho, and parts of present Montana, and Wyoming. (Ore. Laws 1860, 1st reg. sess., pp. 28-30; Van Zandt, p. 155)

Non-county area in Washington Territory lost to creation of SHOSHONE; non-county area eliminated. (Wash. Terr. Laws 1860, 8th sess., pp. 13-14)

YELLOWSTONE (Idaho Territory, extinct) created by Idaho Territory from Non-County Area 2. YELLOWSTONE was located entirely within present Wyoming. (Id. Terr. Laws 1863, loc. and spec., 1st sess., sec. 10/p. 677)

Dakota Territory gained YELLOWSTONE (Idaho Territory, extinct) and most of present Wyoming from Idaho Territory; YELLOWSTONE eliminated. (U.S. Stat., vol. 13, ch. 95 [1864], sec. 18/p. 92; Van Zandt, 134-136, 156-157)

Idaho: Individual County Chronologies