|Counties of Idaho|
|Location||State of Idaho|
|Populations||792 (Clark) – 511,931 (Ada)|
|Areas||408 square miles (1,060 km2) (Payette) – 8,485 square miles (21,980 km2) (Idaho)|
There are 44 counties in the U.S. state of Idaho.
The Idaho Territory was organized in March 1863, and Owyhee County was the first county in the territory to be organized, in December of that year. Oneida County was organized in January 1864, while Missoula County was adopted the same month, before becoming part of the new Montana Territory in May. Shoshone, Nez Perce, Idaho and Boise Counties were recognized in February 1864; Alturas County was organized the same month. In December 1864, Kootenai and Ada Counties were created; Lah-Toh County was also created at this time but was abolished in 1867.
Idaho's present-day boundaries were established in 1868, and Lemhi County was created the following year. By the time Idaho was admitted to the Union as the 43rd state in 1890, a further eight counties had been created, bringing the total to 18. After Canyon, Fremont and Bannock Counties had been created, Alturas and Logan Counties were merged to form Blaine County in March 1895; Lincoln County was formed out of Blaine County later the same month. Bonner and Twin Falls Counties were created in 1907, before a further 21 counties were created between 1911 and 1919, bringing the total to the present-day 44.
Since 1945, each county has used a code on its license plates that features the first letter of the county's name. Where the names of two or more counties start with the same letter, in each of these counties the letter is preceded by a number indicating that county's order in the alphabetical list. For instance, the four counties beginning with 'L' in alphabetical order are Latah, Lemhi, Lewis and Lincoln; the codes for these counties are thus 1L, 2L, 3L and 4L respectively. Elmore, Idaho, Kootenai, Nez Perce, Shoshone, Valley, and Washington Counties are the only ones in the state with their respective first letters; in these counties, the letter alone serves as the code.
|County||FIPS code||County seat||Est.||Origin||License plate prefix||Etymology||Population||Area||Map|
|AdaCounty||001||Boise||1864||Boise County||1A||Ada Riggs (1856-1909), daughter of H. C. Riggs, a member of the Idaho Territorial Legislature.||511,931||1,055 sq mi|
|AdamsCounty||003||Council||1911||Washington County||2A||John Adams (1735-1826), second President of the United States (1797-1801).||4,625||1,365 sq mi|
|BannockCounty||005||Pocatello||1893||Bingham County||1B||Bannock Native American tribe.||88,263||1,113 sq mi|
|Bear LakeCounty||007||Paris||1875||Oneida County||2B||Bear Lake on the Utah/Idaho border.||6,545||971 sq mi|
|BenewahCounty||009||St. Maries||1915||Kootenai County||3B||Ben'wah, chief of the Coeur d'Alene Tribe||9,931||776 sq mi|
|BinghamCounty||011||Blackfoot||1885||Oneida County||4B||Henry H. Bingham (1841-1912), a general in the American Civil War and a U.S. Congressman from Pennsylvania.||48,876||2,095 sq mi|
|BlaineCounty||013||Hailey||1895||Alturas and Logan Counties||5B||James G. Blaine (1830-1893), United States Secretary of State (1881, 1889-1892).||24,766||2,645 sq mi|
|BoiseCounty||015||Idaho City||1864||original county||6B||Boise River||8,094||1,902 sq mi|
|BonnerCounty||017||Sandpoint||1907||Kootenai County||7B||Edwin L. Bonner (1834-1902), originator of an 1864 ferry service on the Kootenai River.||49,491||1,738 sq mi|
|BonnevilleCounty||019||Idaho Falls||1911||Bingham County||8B||Benjamin Bonneville (1796-1878), a French-born explorer of the West.||127,930||1,869 sq mi|
|BoundaryCounty||021||Bonners Ferry||1915||Bonner County||9B||Borders Canada on the north.||12,561||1,269 sq mi|
|ButteCounty||023||Arco||1917||Bingham, Blaine, and Jefferson Counties||10B||Buttes rising from the Snake River Plain.||2,654||2,233 sq mi|
|CamasCounty||025||Fairfield||1917||Blaine County||1C||Camassia, a plant species important as a food source among Native Americans and early settlers.||1,139||1,077 sq mi|
|CanyonCounty||027||Caldwell||1892||Ada County||2C||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.||243,115||590 sq mi|
|CaribouCounty||029||Soda Springs||1919||Bannock County||3C||Caribou Mountains||7,111||1,766 sq mi|
|CassiaCounty||031||Burley||1879||Owyhee County||4C||Disputed, either Cassia Creek or a member of the Mormon Battalion, James John Cazier (1821-1890).||25,164||2,567 sq mi|
|ClarkCounty||033||Dubois||1919||Fremont County||5C||Sam K. Clark (1857-1933), early settler and a member of the Idaho Senate.||792||1,765 sq mi|
|ClearwaterCounty||035||Orofino||1911||Nez Perce County||6C||Clearwater River||8,895||2,462 sq mi|
|CusterCounty||037||Challis||1881||Alturas and Lemhi Counties||7C||General Custer mine, named after George Armstrong Custer (1839-1876), United States Army general.||4,428||4,926 sq mi|
|ElmoreCounty||039||Mountain Home||1889||Alturas County||E||Ida Elmore mines, locally noted for gold and silver production in the 1860s.||28,827||3,078 sq mi|
|FranklinCounty||041||Preston||1913||Oneida County||1F||Franklin D. Richards (1821-1899), early LDS Church apostle.||14,666||666 sq mi|
|FremontCounty||043||Saint Anthony||1893||Bingham County||2F||John C. Frémont (1813-1890), an explorer of the West.||13,592||1,867 sq mi|
|GemCounty||045||Emmett||1915||Boise and Canyon Counties||1G||State nickname of "Gem State."||19,792||563 sq mi|
|GoodingCounty||047||Gooding||1913||Lincoln County||2G||Frank R. Gooding (1859-1928), seventh Governor of Idaho (1905-1909), U.S. Senator (1921-1928).||15,772||731 sq mi|
|IdahoCounty||049||Grangeville||1864||original county||I||Columbia River steamship Idaho launched in 1860. Name predates both Idaho Territory and the State of Idaho.||17,040||8,485 sq mi|
|JeffersonCounty||051||Rigby||1913||Fremont County||1J||Thomas Jefferson (1743-1826), third President of the United States (1801-1809).||32,202||1,095 sq mi|
|JeromeCounty||053||Jerome||1919||Gooding and Lincoln Counties||2J||Disputed, either North Side Irrigation Project developer Jerome Hill, his son-in-law Jerome Kuhn (1898-1952), or his grandson Jerome Kuhn, Jr.||24,662||600 sq mi|
|KootenaiCounty||055||Coeur d'Alene||1864||Nez Perce County||K||Kootenai Native American tribe.||179,789||1,245 sq mi|
|LatahCounty||057||Moscow||1888||Nez Perce County||1L||Latah Creek, Nez Perce for "the place of pine trees and sestle."||40,313||1,077 sq mi|
|LemhiCounty||059||Salmon||1869||Idaho County||2L||Limhi, king of the Nephites according to the Book of Mormon.||8,162||4,564 sq mi|
|LewisCounty||061||Nezperce||1911||Nez Perce County||3L||Meriwether Lewis (1774-1809), a leader of the Lewis and Clark Expedition.||3,715||479 sq mi|
|LincolnCounty||063||Shoshone||1895||Blaine County||4L||Abraham Lincoln (1809-1865), sixteenth President of the United States (1861-1865). Idaho Territory was founded under Lincoln's administration.||5,282||1,206 sq mi|
|MadisonCounty||065||Rexburg||1913||Fremont County||1M||James Madison (1751-1836), fourth President of the United States (1809-1817).||53,881||472 sq mi|
|MinidokaCounty||067||Rupert||1913||Lincoln County||2M||Disputed Native American origin, either Lakota for "a fountain or spring of water" or Shoshoni for "broad expanse."||21,955||760 sq mi|
|Nez PerceCounty||069||Lewiston||1864||original county||N||The Nez Perce, a Native American tribe.||42,454||849 sq mi|
|OneidaCounty||071||Malad City||1864||original county||1O||Oneida Lake in New York state, where many early settlers were from.||4,611||1,200 sq mi|
|OwyheeCounty||073||Murphy||1863||original county||2O||Alternate spelling of Hawaii. Hawaiian fur trappers explored the area in 1819 and 1820.||12,336||7,678 sq mi|
|PayetteCounty||075||Payette||1917||Canyon County||1P||Francois Payette (1793-1844?), Canadian-born fur trader and early settler.||26,350||408 sq mi|
|PowerCounty||077||American Falls||1913||Bingham, Blaine, and Oneida Counties||2P||The American Falls Power Plant||7,950||1,406 sq mi|
|ShoshoneCounty||079||Wallace||1864||original county||S||Shoshone Native American tribe.||13,612||2,634 sq mi|
|TetonCounty||081||Driggs||1915||Bingham, Fremont, and Madison Counties||1T||Teton Range in Wyoming.||12,267||450 sq mi|
|Twin FallsCounty||083||Twin Falls||1907||Cassia County||2T||Twin Falls waterfall on the Snake River.||92,243||1,925 sq mi|
|ValleyCounty||085||Cascade||1917||Boise and Idaho Counties||V||Long Valley located in the county.||12,241||3,733 sq mi|
|WashingtonCounty||087||Weiser||1879||Ada County||W||George Washington (1732-1799), first President of the United States (1789-1797).||10,898||1,456 sq mi|
The Nez Percé are an Indigenous people of the Plateau who are presumed to have lived on the Columbia River Plateau in the Pacific Northwest region for at least 11,500 years.
Nez Perce County is a county located in the U.S. state of Idaho. As of the 2020 census, the population was 42,090. The county seat is Lewiston. The county is named after the Native American Nez Percé tribe. Nez Perce County is part of the Lewiston, Idaho–WA Metropolitan Statistical Area.
Shoshone County is a county in the U.S. state of Idaho. As of the 2020 census, the population was 13,169. The largest city is Kellogg. The county was established in 1864, named for the Native American Shoshone tribe.
Latah County is a county located in the north central region of the U.S. state of Idaho. As of the 2020 census, the population was 39,517. The county seat and largest city is Moscow, the home of the University of Idaho, the state's flagship until 2012 and land-grant university.
Kootenai County is located in the U.S. state of Idaho. In 2020, the United States Census Bureau estimated the county's population at 171,362, making it the third-most populous county in Idaho and by far the largest in North Idaho, the county accounting for 45.4% of the region's total population. The county seat and largest city is Coeur d'Alene. The county was established in 1864 and named after the Kootenai tribe.
Idaho County is a county in the U.S. state of Idaho, and the largest by area in the state. As of the 2020 census, the population was 16,541. The county seat is Grangeville. Previous county seats of the area were Florence (1864–68), Washington (1868–75), and Mount Idaho (1875–1902).
Bonner County is a county in the northern part of the U.S. state of Idaho. As of the 2020 census, the population was 47,110. The county seat and largest city is Sandpoint. Partitioned from Kootenai County and established in 1907, it was named for Edwin L. Bonner, a ferry operator.
Blaine County is a county in the U.S. state of Idaho. As of the 2020 United States Census, the population was 24,272. The county seat and largest city is Hailey. It is also home to the Sun Valley ski resort, adjacent to Ketchum.
Alturas County was a county in Idaho Territory and later the state of Idaho from 1864 to 1895. It covered an area larger than the states of Maryland, New Jersey, and Delaware combined. Most present-day southern Idaho counties were created at least in part from the original Alturas County area. The name Alturas comes from a Spanish word for "mountain summits" or "mountainous heights."
Logan County was a county in Idaho Territory and later the state of Idaho from 1889 to 1895.
Lah-Toh County was a county in Idaho Territory from 1864 to 1867.
Lincoln is the name for several proposals to create a new state in the Northwest United States. The proposed State has been defined in multiple ways, but can generally be said to be coterminous with the region known as the Inland Northwest. The proposed state was named in honor of Abraham Lincoln, who was president during the American Civil War. His name had also been proposed for the states that were eventually named North Dakota and Wyoming.
The Idaho Transportation Department (ITD) is the state of Idaho governmental organization responsible for state transportation infrastructure. This includes ongoing operations and maintenance as well as planning for future needs of the state and its citizens. The agency is responsible for overseeing the disbursement of federal, state, and grant funding for transportation programs in the state.
The 1964 United States presidential election in Idaho took place on November 3, 1964, as part of the 1964 United States presidential election, which was held throughout all 50 states and D.C. Voters chose four representatives, or electors to the Electoral College, who voted for president and vice president.
The history of Idaho in the American Civil War is atypical, as the territory was far from the battlefields.
Fort Lemhi was a mission approximately two miles (3 km) north of present-day Tendoy, Idaho, occupied by Mormon missionaries from 1855 to 1858.
The Lemhi Reservation was a United States Indian Reservation for the Lemhi Shoshone from 1875 to 1907. During almost all this time their main chief was Tendoy.
The following works deal with the cultural, political, economic, military, biographical and geologic history of pre-territorial Idaho, Idaho Territory and the State of Idaho.