Front of the Power County Courthouse, located on Bannock Avenue in American Falls, Idaho, United States. Built in 1925, the courthouse is listed on the National Register of Historic Places. – Ken Lund, CC BY-SA 2.0 – Wikimedia Commons Power County is located in Idaho. About 7,878 people live here (as of 2020). Between 2010 and 2020, the population grew from 7,817 to 7,878. The area covers about 3,736.0 square kilometers. The region is divided into 3 Municipalities. The region was founded in 1913. Power County is county in Idaho, United States. More information at www.co.power.id.us.