Boise County is a county in the U.S. state of Idaho. As of the 2010 census, 7,028 people lived there. The county seat is Idaho City, and Horseshoe Bend is the largest city. It was founded on February 4, 1864.
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.