Boise County is a rural mountain county in the U.S. state of Idaho. As of the 2010 census, the population was 7,028. The county seat is Idaho City, and Horseshoe Bend is its largest city. Boise County is part of the Boise, ID Metropolitan Statistical Area. The Bogus Basin ski area is in the southwestern part of the county. The county's eastern area contains the central section of the Sawtooth Wilderness, the western part of the Sawtooth National Recreation Area.