Geographic center of the United States

Geographic center of the United States, point in Butte County, S. Dak., about 17 mi (27 km) west of Castle Rock. With the admission of Alaska to the union (1959), the geographic center of the United States changed from Smith County, Kans., to Butte County, S. Dak. Later that year, when Hawaii became a state, the point moved 6 mi (10 km) to the west-southwest.