About Power County
Power County covers 1,142 square miles in the southeastern part of the Snake River Basin, with the Snake River passing through its center. Grass-covered hills and rolling mountains cover the southern reaches of the county, and lava fields occupy most everything north of the river, beginning with abrupt cliffs paralleling the banks. Sagebrush also grows in the lower elevations, with higher areas covered by Junipers, willows and other brushes.
The county is named for the American Falls Power Plant on the Snake River, and was organized on January 30, 1913 with its county seat at American Falls. In 1923, construction began on the American Falls Dam and the entire community of American Falls was relocated to the edge of the reservoir, including houses and other buildings.
The Oregon Trail passes through Power County, following the Snake River. Today Interstate 86 follows this same route, with U.S. Highway 30 sharing the same alignment. 7,538 people live here, as of the year 2000, with over half them living in American Falls.
The Deep Creek Mountains extend southward from American Falls to the southern boundary of the county. Arbon Valley lies to the east of the Deep Creek Mountains and Rockland Valley lies to their west side. Deep Creek Peak is the highest point in the county at 8748 feet. The Sublett Mountains cover the southwest corner of the county, on the west of Rockland Valley.