Riverton, city, Fremont County, central Wyoming, at the junction of the Bighorn and Wind rivers (from which the city's name is derived), near the Wind River Indian Reservation; incorporated 1906. It is a commercial and transportation hub in an agricultural region. Lumbering and the extraction of oil and uranium are important to the city's economy. A junior college is here. The city was settled (1906) by homesteaders in a land rush. Population 9,588 (1980); 9,202 (1990); 9,310 (2000).