river rising in northeastern New Mexico, U.S., near Capulin Mountain National Monument and flowing 698 mi (1,123 km) to enter the Arkansas River near Tulsa, Okla. From its source, the Cimarron flows east past Black Mesa, a peak 4,973 ft (1,516 m) high, through the northern Oklahoma Panhandle and bends northward through the southeastern corner of Colorado and the southwestern corner of Kansas. The riverbed in this area is dry except during spring and early summer or during occasional floods. South of Coldwater, Kan., the Cimarron reenters Oklahoma as a permanent stream.

The river probably derives its name from cimarrón, Spanish for “wild.” Although unnavigable, it has played an important part in the history of the western United States. The direct route of the Santa Fe Trail coursed along its valley for 100 mi in southwestern Kansas, and travellers knew the Oklahoma Panhandle as the “Cimarron Cutoff.”

There are no cities of any size on the river, but near its banks are Guthrie, Kingfisher, Fairview, Cushing, and Yale, in Oklahoma, and Folsom, in New Mexico. Chief tributaries are North Fork and Crooked Creek.