Idaho Counties

The following lists the counties in the state of Idaho, the date each was created, and the parent county/counties:

• Ada:  1864, Boise
• Adams:  1911, Washington
• Alturas:  1863, original (discontinued)
• Bannock:  1893, Bear Lake and Oneida
  
• Bear Lake:  1875, Oneida
• Benewah:  1915, Kootenai
• Bingham:  1885, Oneida
• Blaine:  1895, Alturas
• Boise:  1864, original
• Bonner:  1907, Kootenai
• Bonneville:  1911, Bingham
• Boundary:  1915, Bonner
• Butte:  1917, Bingham, Blaine, and Jefferson
• Camas:  1917, Blaine
• Canyon:  1892, Ada and Owyhee
• Caribou:  1919, Bannock and Oneida
• Cassia:  1879, Oneida
• Clark:  1919, Fremont
• Clearwater:  1911, Nez Perce
• Custer:  1881, Alturas
• Elmore:  1889, Ada and Alturas
• Franklin:  1913, Oneida
• Fremont:  1893, Bingham and Lemhi
• Gem:  1915, Boise and Canyon
• Gooding:  1913, Lincoln
• Idaho:  1864, original
• Jefferson:  1913, Fremont
• Jerome:  1919, Gooding and Lincoln
• Kootenai:  1864, Nez Perce
• Latah:  1888, Nez Perce
• Lemhi:  1869, Idaho
• Lewis:  1911, Nez Perce
• Lincoln:  1895, Alturas
• Madison:  1913, Fremont
• Minidoka:  1913, Lincoln
• Nez Perce:  1861, original
• Oneida:  1865, original
• Owyhee:  1863, original
• Payette:  1917, Canyon
• Power:  1913, Bingham, Blaine, and Oneida
• Shoshone:  1864, original
• Teton:  1915, Bingham, Fremont, and Madison
• Twin Falls:  1907, Cassia
• Valley:  1917, Boise and Idaho
• Washington:  1879, Boise