Belle Fourche is located in Butte County (of which it is the county seat) northwest of Rapid City between Sturgis and the Wyoming state line at the intersection of US 85 and US 212 on the banks of the Belle Fourch River near the Black Hills National Forest, in Black Hills, Badlands & Lakes Region.
The geographic center of the total land mass of the United States is located about 20 miles north of Belle Fourche. The site is on the open prairie and it is marked by a sign and a rock tower known as sheepherder's monument or Stone Johnnie.
The population estimate for July 1, 1998 was 4,907, an increase of 572 since 1990.