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