Camas County is a county in the southern portion of the U.S. state of Idaho. The county seat and largest city is Fairfield. The county was established 107 years ago in 1917 by the Idaho Legislature with a partition of Blaine County on February 6. 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.