Middle Fork Cimarron River is a 10.3-mile-long (16.6 km) tributary of the Cimarron River in Colorado. The river's source is east of Coxcomb Peak in the Uncompahgre Wilderness of Hinsdale County. It joins the East Fork Cimarron River in Gunnison County to form the Cimarron River, and is impounded by Silver Jack Dam.