Belle Fourche

River rising in Campbell County, northeast Wyoming, USA, that flows through Wyoming and South Dakota states and joins the Cheyenne River (which flows into Lake Oahe) in Haakon County, South Dakota; length 467 km/290 mi.

Course The river flows generally northeast from its source into Crook County, through the Keyhole Reservoir and past Devils Tower, before turning southeast and entering South Dakota. There, it flows generally eastwards past Belle Fourche and then through a sparsely populated region to the Cheyenne.

The Belle Fourche Reservoir, 16 km/10 mi long and 5 km/3 mi wide, impounded by the Belle Fourche Dam (1911), is on Owl Creek, a tributary of the Belle Fourche that drains the northern part of the Black Hills and irrigates an area of 194,250 sq km/75,000 sq mi.

Belle Fourche

City and administrative headquarters of Butte County in southwestern Dakota, 21 km/13 mi north of Spearfish, at the confluence of Redwater Creek and the Belle Fourche River; population (2000) 4,700. It was settled in 1878 and became the railhead and trade centre for a three-state area (Dakota, Wyoming, Montana) producing cattle, sugar beets, wool, and bentonite. Its annual Black Hills Roundup in July draws visitors.