Clark County, Idaho

Clark County is Idaho’s least populated county, tucked away in the eastern part of the state along the Montana border. Here, cattle can easily outnumber people, and the vast open landscape gives the county an unmistakably remote, rural character.

Dubois, the county seat, is a tiny community that feels more like a quiet stop along the highway than a traditional town. The area is dominated by high desert terrain, with the Beaverhead Mountains rising to the north. Ranching remains the main industry, so working ranches and cattle are far more common than tourists.

The scenery may look stark, but its rugged beauty is part of the appeal. Harriman State Park extends into the broader region, adding opportunities for outdoor recreation. However, Clark County’s population has been declining for decades, reinforcing its reputation as one of Idaho’s most remote and sparsely populated areas.

CategoryDetails
County NameClark County
County SeatDubois
EtymologyNamed after Dubois Sam K. Clark, member of the Idaho Senate
Cities, Towns, and CommunitiesDubois, Spencer, and more
Interstates and HighwaysU.S. Route 20, Idaho State Highway 33
FIPS Code16-033
Total Area1,550 square miles (land: 1,540 sq mi; water: 10 sq mi)
Adjacent CountiesLemhi County (West), Butte County (Southwest), Jefferson County (South), Fremont County (East), Beaverhead County, Montana (North)
Time ZoneMountain Time Zone
StateIdaho
Coordinates43.4° N, 112.4° W
Major LandmarksCraters of the Moon National Monument, Henry’s Lake, Island Park Reservoir
Population1,500
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