It is named for the camas root, or Camassia, a lily-like plant with an edible bulb found in the region, that Native Americans and settlers used as a food source.

Camas County is part of the Hailey, ID Micropolitan Statistical Area.

Native presence on the Camas Prairie dates back over 11,000 years ago.

Explorer, Donald Mackenzie discovered the Camas Prairie by 1820 and the area slowly grew in importance as a travel route.

Military escorts for wagon trains headed to Oregon started using the route through the Camas Prairie in 1852.

When the cavalry was stationed at Fort Boise the southern portion of the Camas Prairie was an important feeding ground for their horses.

While the Lava mining district near Fairfield was active in the 1880s, Camas County's settlements were primarily agricultural.

At the 1890 Census, Alturas County contained the Little Smoky precinct with 95 residents while Logan County contained the Corral, Crichton, Soldier, and Spring Creek precincts with a combined population of 805.

In 1891, the Idaho Legislature attempted to transfer all five Camas precincts to a new county named Alta.

The railroad's arrival led the majority of settlement in Soldier to locate to what became known as Fairfield.

[citation needed] As of the 2010 census, there were 1,117 people, 487 households, and 326 families living in the county.

[18] In terms of ancestry, 24.8% were German, 20.2% were American, 15.1% were English, 8.8% were Irish, and 7.3% were Swedish.

22.20% of all households were made up of individuals, and 8.30% had someone living alone who was 65 years of age or older.

The Soldier Mountain ski area, opened 77 years ago in 1948, is twelve miles (20 km) north of Fairfield, in the Soldier Mountains of the Sawtooth National Forest.

[23] The county is in the catchment area, but not the taxation zone, for College of Southern Idaho.