One interpretation holds that in ancient times, the Dolores River flowed through Unaweep Canyon and into the Gunnison River south of present day Grand Junction, Colorado. A second interpretation is that the Gunnison River itself once flowed through the canyon (Kaplan 2005). In either case as the uplift of the Uncompahgre Plateau between 5 and 15 million years ago resulted in the course change of the river involved and left the canyon without a river. A third, controversial hypothesis holds that the steep sides of the canyon in places indicates the valley was glaciated during the Late Paleozoic (Soreghan, G.S. 2004) or Pleistocene. However, seismic studies indicate that the flat valley floor is a V-shaped valley that was filled by tallus and alluvial fill (Oesleby 2005).
Today two creeks flow out of the caynon, East Canyon Creek and West Canyon Creek, separated by Unaweep Divide nearer the east end of the canyon.
Unaweep Canyon is home to a small, but growing number of residents. The Gateway Canyons Resort in Gateway, Colorado employs a significant number of the local residents.