The Colorado River is about 1,450 miles in length and runs through Colorado, Utah, Arizona, Nevada, and California (specifically Baja California and Sonora), and ending in Mexico. It begins at La Poudre Pass Lake in Rocky Mountain National Park, and continues into various reservoirs and tributaries, and finally ending in its delta in Mexico.

http://insightsdels.nas.edu/?p=43

Area map of Colorado River

http://wwwpaztcn.wr.usgs.gov/fscc/stanton-repeat-photography/repeat-photos.php?mode=photo&PID=489

1890 photo of the upper Colorado River