List of counties in Idaho

This is a list of 44 counties in the U.S. state of Idaho.

Each county in Idaho has a license plate prefix, according to the first letter of the county name. The first county for a given letter is given #1, the second county #2, etc. For example, Ada and Adams are the only two counties with the letter 'A'. Since Ada comes before Adams alphabetically, Ada is '1A' while Adams is '2A.' There are four counties that start with the letter 'L': Latah, Lemhi, Lewis, and Lincoln; the license plate prefixes for these counties are 1L, 2L, 3L, and 4L, respectively.

Elmore, Idaho, Kootenai, Nez Perce, Shoshone, Valley, and Washington counties are the only ones in the state with those beginning letters. Therefore, the license plate prefix would be the first letter of the county name, without a number. The letter 'B' has ten counties, 'C' has seven, and 'L' has four; the remaining letters have two or fewer.

When the Idaho Territory was created in March 1863, there were five original counties: Shoshone, Nez Perce, Idaho, Boise, and Missoula. Kootenai, Owyhee, and Oneida were created by 1865, Ada was created in 1866, and when the territory reached Idaho's present day dimensions in 1868, Lemhi was formed. By 1880, 13 counties were created. Ten years later, when Idaho became a state, 18 counties were created. In 1893, Fremont and Bannock counties were created. By 1900, Idaho had 21 counties. Ten years later, only two new counties were created. Between 1910 and 1920, 21 new counties were created, bringing the number of counties to 44, where it remains today.

Alphabetical list

County
FIPS code
[1]
County seat
[2]
Established
[2]
Origin
[3]
Etymology
[4]
Population
[2][5]
Area
[2][5]
Map
Ada County 001 Boise 1864 Boise County Ada Riggs, daughter of H. C. Riggs, a member of the Idaho Territorial Legislature. 392,365 1,055 sq mi
(2,732 km2)
State map highlighting Ada County
Adams County 003 Council 1911 Washington County John Adams (1735-1826), second President of the United States (1797-1801). 3,976 1,365 sq mi
(3,535 km2)
State map highlighting Adams County
Bannock County 005 Pocatello 1893 Bingham County Bannock Native American tribe. 82,839 1,113 sq mi
(2,883 km2)
State map highlighting Bannock County
Bear Lake County 007 Paris 1893 Oneida County Bear Lake on the Utah/Idaho border. 5,986 971 sq mi
(2,515 km2)
State map highlighting Bear Lake County
Benewah County 009 St. Maries 1915 Kootenai County Ben'wah, chief of the Coeur d'Alene Tribe 9,285 776 sq mi
(2,010 km2)
State map highlighting Benewah County
Bingham County 011 Blackfoot 1885 Oneida County Henry H. Bingham (1841-1912), a general in the American Civil War and a U.S. Congressman from Pennsylvania. 45,607 2,095 sq mi
(5,426 km2)
State map highlighting Bingham County
Blaine County 013 Hailey 1895 Alturas County James G. Blaine (1830-1893), United States Secretary of State (1881, 1889-1892). 21,376 2,645 sq mi
(6,851 km2)
State map highlighting Blaine County
Boise County 015 Idaho City 1864 Original county Boise River 7,028 1,902 sq mi
(4,926 km2)
State map highlighting Boise County
Bonner County 017 Sandpoint 1907 Kootenai County Edwin L. Bonner, originator of an 1864 ferry service on the Kootenai River. 40,877 1,738 sq mi
(4,501 km2)
State map highlighting Bonner County
Bonneville County 019 Idaho Falls 1911 Bingham County Benjamin Bonneville (1796-1878), a French-born explorer of the West. 104,234 1,869 sq mi
(4,841 km2)
State map highlighting Bonneville County
Boundary County 021 Bonners Ferry 1915 Bonner Borders Canada on the north. 10,972 1,269 sq mi
(3,287 km2)
State map highlighting Boundary County
Butte County 023 Arco 1917 Bingham, Blaine, and Jefferson counties Buttes rising from the Snake River Plain. 2,891 2,233 sq mi
(5,783 km2)
State map highlighting Butte County
Camas County 025 Fairfield 1917 Blaine County Camassia, a plant species important as a food source among Native Americans and early settlers. 1,117 1,075 sq mi
(2,784 km2)
State map highlighting Camas County
Canyon County 027 Caldwell 1892 Ada County Disputed, either a canyon of the Boise River near Caldwell or a canyon of the Snake River which forms part of the county's boundary. 188,923 590 sq mi
(1,528 km2)
State map highlighting Canyon County
Caribou County 029 Soda Springs 1919 Bannock County Caribou Mountains 6,963 1,766 sq mi
(4,574 km2)
State map highlighting Caribou County
Cassia County 031 Burley 1879 Owyhee County Disputed, either Cassia Creek or a member of the Mormon Battalion, James John Cazier. 22,952 2,567 sq mi
(6,648 km2)
State map highlighting Cassia County
Clark County 033 Dubois 1919 Fremont County Sam K. Clark, early settler and a member of the Idaho Senate. 982 1,765 sq mi
(4,571 km2)
State map highlighting Clark County
Clearwater County 035 Orofino 1911 Nez Perce County Clearwater River 8,761 2,462 sq mi
(6,377 km2)
State map highlighting Clearwater County
Custer County 037 Challis 1881 Alturas and Lemhi counties General Custer mine, named after George Armstrong Custer (1839-1876), United States Army general. 4,368 4,926 sq mi
(12,758 km2)
State map highlighting Custer County
Elmore County 039 Mountain Home 1889 Alturas County Ida Elmore mines, locally noted for gold and silver production in the 1860s. 27,038 3,078 sq mi
(7,972 km2)
State map highlighting Elmore County
Franklin County 041 Preston 1913 Oneida County Franklin D. Richards (1821-1899), early LDS Church apostle. 12,786 666 sq mi
(1,725 km2)
State map highlighting Franklin County
Fremont County 043 Saint Anthony 1893 Bingham County John C. Frémont (1813-1890), an explorer of the West. 13,242 1,867 sq mi
(4,836 km2)
State map highlighting Fremont County
Gem County 045 Emmett 1915 Boise and Canyon counties State nickname of "Gem State." 16,719 563 sq mi
(1,458 km2)
State map highlighting Gem County
Gooding County 047 Gooding 1913 Lincoln County Frank R. Gooding (1859-1928), seventh Governor of Idaho (1905-1909), U.S. Senator (1921-1928). 15,464 731 sq mi
(1,893 km2)
State map highlighting Gooding County
Idaho County 049 Grangeville 1864 Original county Columbia River steamship Idaho launched in 1860. Name predates both Idaho Territory and the State of Idaho. 16,267 8,485 sq mi
(21,976 km2)
State map highlighting Idaho County
Jefferson County 051 Rigby 1913 Fremont County Thomas Jefferson (1743-1826), third President of the United States (1801-1809). 26,140 1,095 sq mi
(2,836 km2)
State map highlighting Jefferson County
Jerome County 053 Jerome 1919 Gooding and Lincoln counties Disputed, either North Side Irrigation Project developer Jerome Hill, his son-in-law Jerome Kuhn, or his grandson Jerome Kuhn, Jr. 22,374 600 sq mi
(1,554 km2)
State map highlighting Jerome County
Kootenai County 055 Coeur d'Alene 1864 Nez Perce County Kootenai Native American tribe. 138,494 1,245 sq mi
(3,225 km2)
State map highlighting Kootenai County
Latah County 057 Moscow 1888 Nez Perce County Latah Creek, Nez Perce for "the place of pine trees and sestle." 37,244 1,077 sq mi
(2,789 km2)
State map highlighting Latah County
Lemhi County 059 Salmon 1869 Idaho County Limhi, king of the Nephites according to the Book of Mormon. 7,936 4,564 sq mi
(11,821 km2)
State map highlighting Lemhi County
Lewis County 061 Nezperce 1911 Nez Perce County Meriwether Lewis (1774-1809), a leader of the Lewis and Clark Expedition. 3,821 479 sq mi
(1,241 km2)
State map highlighting Lewis County
Lincoln County 063 Shoshone 1895 Logan County Abraham Lincoln (1809-1865), sixteenth President of the United States (1861-1865). Idaho Territory was founded under Lincoln's administration. 5,208 1,206 sq mi
(3,124 km2)
State map highlighting Lincoln County
Madison County 065 Rexburg 1913 Fremont County James Madison (1751-1836), fourth President of the United States (1809-1817). 37,536 472 sq mi
(1,222 km2)
State map highlighting Madison County
Minidoka County 067 Rupert 1913 Lincoln County Disputed Native American origin, either Lakota for "a fountain or spring of water" or Shoshoni for "broad expanse." 20,069 760 sq mi
(1,968 km2)
State map highlighting Minidoka County
Nez Perce County 069 Lewiston 1864 Original county The Nez Perce, a Native American tribe. 39,265 849 sq mi
(2,199 km2)
State map highlighting Nez Perce County
Oneida County 071 Malad City 1864 Original County Oneida Lake in New York state, where many early settlers were from. 4,286 1,200 sq mi
(3,108 km2)
State map highlighting Oneida County
Owyhee County 073 Murphy 1863 Original county Alternate spelling of Hawaii. Hawaiian fur trappers explored the area in 1819 and 1820. 11,526 7,678 sq mi
(19,886 km2)
State map highlighting Owyhee County
Payette County 075 Payette 1917 Canyon County Francois Payette (1793-1844?), Canadian-born fur trader and early settler. 22,623 408 sq mi
(1,057 km2)
State map highlighting Payette County
Power County 077 American Falls 1913 Bingham, Blaine, and Oneida counties The American Falls Power Plant 7,817 1,406 sq mi
(3,642 km2)
State map highlighting Power County
Shoshone County 079 Wallace 1864 Original county Shoshone Native American tribe. 12,765 2,634 sq mi
(6,822 km2)
State map highlighting Shoshone County
Teton County 081 Driggs 1915 Bingham, Fremont, and Madison counties Teton Range and valley. 10,170 450 sq mi
(1,165 km2)
State map highlighting Teton County
Twin Falls County 083 Twin Falls 1907 Cassia County Twin Falls waterfall on the Snake River. 77,230 1,925 sq mi
(4,986 km2)
State map highlighting Twin Falls County
Valley County 085 Cascade 1917 Boise and Idaho counties Long Valley located in the county. 9,862 3,733 sq mi
(9,668 km2)
State map highlighting Valley County
Washington County 087 Weiser 1879 Ada County George Washington (1732-1799), first President of the United States (1789-1797). 10,198 1,456 sq mi
(3,771 km2)
State map highlighting Washington County

Defunct Idaho counties

References

  1. "EPA County FIPS Code Listing". EPA.gov. Retrieved 2008-02-23.
  2. 2.0 2.1 2.2 2.3 National Association of Counties. "NACo - Find a county". Retrieved 2008-04-26.
  3. Hailey, John (1910). The History of Idaho. Press of Syms-York company. pp. 305–307. OCLC 5793481. Retrieved 2008-04-26.
  4. "List of Idaho Counties - Idaho.gov". State of Idaho. Retrieved 2008-07-30.
  5. 5.0 5.1 "Idaho QuickFacts". U.S. Census Bureau. Retrieved 2008-04-23. (2000 Census)