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| County | Date Formed | County Seat | Parent County | County Coordinator (CC) |
|---|---|---|---|---|
| Ada | 22 Dec 1864 | Boise | Boise | Available |
| Adams | 3 Mar 1911 | Council | Washington | Available |
| Alturas (defunct) | 1864-1895 | Original county | See Blaine County | |
| Bannock | 6 Mar 1893 | Pocatello | Bingham | Available |
| Bear Lake | 5 Jan 1875 | Paris | Oneida | Shirlene Jensen |
| Benewah | 23 Jan 1915 | Saint Maries | Kootenai | Karen Wendell |
| Bingham | 13 Jan 1885 | Blackfoot | Oneida | Available |
| Blaine | 5 Mar 1895 | Hailey | Alturas | Available |
| Boise | 4 Feb 1864 | Idaho City | Original county | Available |
| Bonner | 21 Feb 1907 | Sandpiper | Kootenai | Randy Cummings |
| Bonneville | 7 Feb 1911 | Idaho Falls | Bingham | Available |
| Boundary | 23 Jan 1915 | Bonners Ferry | Bonner | Randy Cummings |
| Butte | 6 Feb 1917 | Arco | Bingham, Blaine, and Jefferson | Available |
| Camas | 6 Feb 1917 | Fairfield | Blaine | Available |
| Canyon | 7 Mar 1891 | Caldwell | Ada | Norma Hass |
| Caribou | 11 Feb 1919 | Soda Springs | Bannock | Available |
| Cassia | 20 Feb 1879 | Burley | Owyhee | Available |
| Clark | 1 Feb 1919 | Dubois | Fremont | Available |
| Clearwater | 27 Feb 1911 | Orofino | Nez Perce | Michal Beck |
| Custer | 8 Jan 1881 | Challis | Alturas and Lemhi | Available |
| Elmore | 7 Feb 1889 | Mountain Home | Alturas | Available |
| Franklin | 20 Jan 1913 | Preston | Oneida | Available |
| Fremont | 4 Mar 1893 | Saint Anthony | Bingham | Available |
| Gem | 15 Mar 1915 | Emmett | Boise and Canyon | Available |
| Gooding | 28 Jan 1913 | Gooding | Lincoln | Available |
| Idaho | 4 Feb 1864 | Grangeville | Original county | Penny Casey |
| Jefferson | 18 Feb 1913 | Rigby | Fremont | Kerry Hairston |
| Jerome | 8 Feb 1919 | Jerome | Gooding & Lincoln | Available |
| Kootenai | 22 Dec 1864 | Coeur d'Alene | Nez Perce | Available |
| Lah-Toh (defunct) | 1864-1867 | Unknown | N/A | |
| Latah | 14 May 1888 | Moscow | Nez Perce | Norma Hass |
| Lemhi | 9 Jan 1869 | Salmon | Idaho | Available |
| Lewis | 3 Mar 1911 | Nezperce | Nez Perce | Available |
| Lincoln | 18 Mar 1895 | Shoshone | Alturas & Blaine | Available |
| Logan (defunct) | 1889-1895 | Alturas | N/A | |
| Madison | 18 Feb 1913 | Rexburg | Fremont | Available |
| Minidoka | 28 Jan 1913 | Rupert | Lincoln | Available |
| Nez Perce | 4 Feb 1864 | Lewiston | Original county | Natalie Huntley |
| Oneida | 22 Jan 1864 | Malad City | Original county | Available |
| Owyhee | 31 Dec 1863 | Murphy | Original county | Available |
| Payette | 28 Feb 1917 | Payette | Canyon | Kerrie Taylor |
| Power | 30 Jan 1913 | American Falls | Bingham, Blaine, & Oneida | Available |
| Shoshone | 4 Feb 1864 | Wallace | Original county | Randy Cummings |
| Teton | 26 Jan 1915 | Driggs | Madison | Available |
| Twin Falls | 21 Feb 1907 | Twin Falls | Cassia | Available |
| Valley | 26 Feb 1917 | Cascade | Idaho & Boise | Available |
| Washington | 20 Feb 1879 | Weiser | Boise | Scot Stout |
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This page was last updated
01/26/2026