The Belle Fourche River (pronounced bel FOOSH; Lakota: Šahíyela Wakpá) is a tributary of the Cheyenne River, approximately 290 miles (470 km) long, in the U.S. states of Wyoming and South Dakota. It is part of the Mississippi River watershed via the Cheyenne and Missouri rivers. In the latter part of the 19th century, the Belle Fourche River was known as the North Fork of the Cheyenne River. Belle Fourche is a name derived from French meaning "beautiful fork".It rises in northeastern Wyoming, in southern Campbell County, approximately 15 miles (24 km) north of Wright. It flows northeast around the ... Source: Wikipedia