The Colorado River, Mojave language Aha Kwahwat, (Red River or Red-like River), is a river in the Southwestern United States and northwestern Mexico, approximately 2330 km (1447.8 mi) long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers 637000 km2 (245947.1 sqmi) in parts of seven U.S. states and two Mexican states. The natural course of the river flows from the Continental Divide at La Poudre Pass in Rocky Mountain National Park, Colorado, into the Gulf of California between the Baja California peninsula and mainland Mexico.
Large diversions of water for irrigation, and to a much lesser extent to supply cities combined with significant evaporation losses from its reservoirs have dewatered the lower course of the river downstream of Yuma, AZ, above the Colorado River Delta, resulting in it no longer consistently reaching the Gulf of California. More than 20 major dams have been built on the Colorado River and its tributaries.