List of Counties in Idaho
Idaho has 44 counties. The most populous counties are Ada County (Boise), Canyon County, Kootenai County, Bonneville County, Bannock County, Twin Falls County, Bonner County, Bingham County, Nez Perce County, and Madison County. Ada County, which includes the state capital Boise, is the largest by population and serves as Idaho’s economic and political center. Canyon County, part of the Boise metropolitan area, is also rapidly growing. The rest of the state has a mix of small urban and large rural counties, with significant agricultural and natural resource industries.
List of All Counties in Idaho
- Ada County, Idaho
- Adams County, Idaho
- Bannock County, Idaho
- Bear Lake County, Idaho
- Benewah County, Idaho
- Bingham County, Idaho
- Blaine County, Idaho
- Boise County, Idaho
- Bonner County, Idaho
- Bonneville County, Idaho
- Boundary County, Idaho
- Butte County, Idaho
- Camas County, Idaho
- Canyon County, Idaho
- Caribou County, Idaho
- Cassia County, Idaho
- Clark County, Idaho
- Clearwater County, Idaho
- Custer County, Idaho
- Elmore County, Idaho
- Franklin County, Idaho
- Fremont County, Idaho
- Gem County, Idaho
- Gooding County, Idaho
- Idaho County, Idaho
- Jefferson County, Idaho
- Jerome County, Idaho
- Kootenai County, Idaho
- Latah County, Idaho
- Lemhi County, Idaho
- Lewis County, Idaho
- Lincoln County, Idaho
- Madison County, Idaho
- Minidoka County, Idaho
- Nez Perce County, Idaho
- Oneida County, Idaho
- Owyhee County, Idaho
- Payette County, Idaho
- Power County, Idaho
- Shoshone County, Idaho
- Teton County, Idaho
- Twin Falls County, Idaho
- Valley County, Idaho
- Washington County, Idaho
1. Idaho County
Overview
Idaho County is the largest county in Idaho by land area, located in the west-central part of the state. It is bordered by several counties, including Clearwater County to the north and Valley County to the south. The county seat is Grangeville, a small town with a rich history rooted in mining, agriculture, and logging. Idaho County is known for its rugged and diverse landscape, which includes the Bitterroot Mountains, the Salmon River, and parts of the Nez Perce National Historical Park. Much of the county is covered by national forests, making it a prime destination for outdoor enthusiasts interested in activities like hunting, fishing, and hiking. Established in 1864, Idaho County was a key player in the state’s early gold rush days and continues to be a center for timber and agriculture.
County Facts
- Population: Approximately 16,000 (2023 estimate)
- County Seat: Grangeville
- Major Airports: Idaho County Airport (Grangeville)
- Major Highways: US-95, State Highway 13
2. Owyhee County
Overview
Owyhee County, located in southwestern Idaho, is the second-largest county in the state by land area. It is bordered by Nevada to the south and Oregon to the west. The county seat is Murphy, a small town that reflects the county’s rural and agricultural nature. Owyhee County is known for its vast and remote high desert landscapes, including the Owyhee River Canyon and the Bruneau River. The county has a rich history of cattle ranching, mining, and Native American culture. Established in 1863, Owyhee County was named after a group of Hawaiian fur trappers who went missing in the area. The economy today remains centered on agriculture, particularly cattle ranching, and mining.
County Facts
- Population: Approximately 12,000 (2023 estimate)
- County Seat: Murphy
- Major Airports: Murphy Airport
- Major Highways: US-95, State Highway 78, State Highway 51
3. Lemhi County
Overview
Lemhi County is located in eastern Idaho, along the state’s border with Montana. It is bordered by Custer County to the south and Ravalli County, Montana, to the north. The county seat is Salmon, a historic town known for its connection to the Lewis and Clark Expedition. Lemhi County is home to some of Idaho’s most pristine wilderness areas, including the Frank Church-River of No Return Wilderness and the Lemhi Range. The county’s economy is largely based on agriculture, with cattle ranching and hay production playing major roles, as well as outdoor recreation and tourism. Lemhi County was established in 1869 and has a deep historical connection to Native American tribes, such as the Shoshone and Nez Perce, and early American explorers.
County Facts
- Population: Approximately 8,000 (2023 estimate)
- County Seat: Salmon
- Major Airports: Lemhi County Airport (Salmon)
- Major Highways: US-93, State Highway 28
4. Cassia County
Overview
Cassia County is located in southern Idaho, bordered by Twin Falls County to the west and Power County to the east. The county seat is Burley, which serves as the main economic and agricultural hub for the region. Cassia County’s landscape is varied, including portions of the Snake River Plain and the Albion Mountains. The county has a strong agricultural base, with crops like sugar beets, potatoes, and wheat playing a significant role in the local economy. Additionally, the county is known for its outdoor recreational opportunities, with areas like the City of Rocks National Reserve drawing rock climbers and hikers. Cassia County was established in 1879, and its development has been closely tied to irrigation projects that transformed the once-arid region into fertile farmland.
County Facts
- Population: Approximately 25,000 (2023 estimate)
- County Seat: Burley
- Major Airports: Burley Municipal Airport
- Major Highways: I-84, US-30, State Highway 27
5. Custer County
Overview
Custer County is located in central Idaho, known for its rugged mountain landscapes and wilderness areas. It is bordered by Lemhi County to the north and Blaine County to the south. The county seat is Challis, a small town with a rich history in mining and ranching. Custer County is home to the highest peaks in Idaho, including Borah Peak, which is the tallest mountain in the state. Much of the county is within the boundaries of the Salmon-Challis National Forest, offering ample opportunities for hiking, fishing, and hunting. The economy of Custer County is primarily based on mining, agriculture, and tourism. Established in 1881, the county has a storied history that includes both Native American heritage and the legacy of gold and silver mining.
County Facts
- Population: Approximately 4,300 (2023 estimate)
- County Seat: Challis
- Major Airports: Challis Airport
- Major Highways: US-93, State Highway 75, State Highway 21
6. Elmore County
Overview
Elmore County is located in southwestern Idaho and is bordered by Ada County to the west and Blaine County to the east. The county seat is Mountain Home, which is home to Mountain Home Air Force Base, a major employer in the region. Elmore County’s geography is diverse, ranging from the Snake River Plain to mountainous areas like the Danskin and Sawtooth ranges. The county has a strong military presence due to the Air Force base, and its economy also includes agriculture, particularly cattle ranching and crop production, and tourism. Established in 1889, Elmore County is named after the Ida Elmore Mines, a gold and silver mining operation that once operated in the area.
County Facts
- Population: Approximately 30,000 (2023 estimate)
- County Seat: Mountain Home
- Major Airports: Mountain Home Municipal Airport
- Major Highways: I-84, US-20, State Highway 51
7. Blaine County
Overview
Blaine County is located in south-central Idaho, bordered by Custer County to the north and Lincoln County to the south. The county seat is Hailey, while nearby Sun Valley is one of the most famous resort towns in the U.S., known for its skiing and year-round outdoor activities. Blaine County’s economy is heavily reliant on tourism, with Sun Valley and Ketchum drawing visitors for skiing, hiking, and other recreational pursuits. The county is also known for its arts and cultural events, including the Sun Valley Film Festival. Established in 1895, Blaine County has long been a destination for outdoor enthusiasts and wealthy visitors, but it also has a strong agricultural tradition, particularly in ranching.
County Facts
- Population: Approximately 25,000 (2023 estimate)
- County Seat: Hailey
- Major Airports: Friedman Memorial Airport (Hailey)
- Major Highways: US-20, US-26, State Highway 75
8. Valley County
Overview
Valley County is located in west-central Idaho, bordered by Idaho County to the north and Boise County to the south. The county seat is Cascade, while McCall, another major town, is known for its outdoor recreation opportunities, especially skiing and boating. Valley County is home to Payette Lake, Brundage Mountain, and large portions of the Boise and Payette National Forests. The economy of Valley County is largely based on tourism, particularly during the winter and summer months when visitors come for skiing, hiking, and water sports. Established in 1917, Valley County has a history rooted in forestry, ranching, and outdoor recreation.
County Facts
- Population: Approximately 12,000 (2023 estimate)
- County Seat: Cascade
- Major Airports: McCall Municipal Airport
- Major Highways: State Highway 55, State Highway 21
9. Bonneville County
Overview
Bonneville County is located in eastern Idaho, bordered by Wyoming to the east and Bingham County to the west. The county seat is Idaho Falls, the largest city in the county and a major economic hub for the region. Bonneville County’s economy is diverse, with key sectors including energy production, healthcare, and agriculture. Idaho Falls is home to the Idaho National Laboratory, a major nuclear research facility that employs thousands in the area. The county’s agricultural production includes potatoes, wheat, and barley. Established in 1911, Bonneville County was named after explorer Benjamin Bonneville, who charted much of the American West.
County Facts
- Population: Approximately 130,000 (2023 estimate)
- County Seat: Idaho Falls
- Major Airports: Idaho Falls Regional Airport
- Major Highways: I-15, US-26, US-91
10. Kootenai County
Overview
Kootenai County is located in northern Idaho, bordered by Washington State to the west and Shoshone County to the east. The county seat is Coeur d’Alene, a city known for its beautiful lake and thriving tourism industry. Kootenai County has become a popular destination for both tourists and new residents, thanks to its outdoor activities, including boating, hiking, and skiing, as well as its strong economy driven by healthcare, manufacturing, and retail. Established in 1864, Kootenai County was named after the Kootenai Native American tribe. The county has experienced rapid growth in recent decades, becoming one of the fastest-growing regions in the state.
County Facts
- Population: Approximately 180,000 (2023 estimate)
- County Seat: Coeur d’Alene
- Major Airports: Coeur d’Alene Airport (Pappy Boyington Field)
- Major Highways: I-90, US-95