Clark County is a rural county in the U.S. state of Idaho; its county seat and largest city is Dubois. As of the 2020 census, the population was 790, making it the least populous county in the state.

Fremont County is a county located in the U.S. state of Idaho. As of the 2020 census the county had a population of 13,388. The county seat and largest city is St. Anthony. The county was established in 1893, and was named for the explorer John C. Frémont. Fremont County is part of the Rexburg, Idaho micropolitan area, which is also included in the Idaho Falls metropolitan area.