The Imperial Reservoir is an artificial lake formed by the construction of the Imperial Diversion Dam across the Colorado River in the Lower Colorado River Valley of Imperial County, California, and Yuma County, Arizona. It is 16 miles (26 km) northeast of Yuma, Arizona.

Dry washes are the major watershed feed systems to Imperial Reservoir. The next upstream major watershed feeder is the Bill Williams River from western Arizona. Upstream on the Colorado River, the basic feeder watershed to Imperial Reservoir is the Havasu-Mojave Lakes Watershed of Lake Havasu.

The Senator Wash flows eastward from California into the reservoir. The Wash is blocked by Senator Wash Dam to form the Senator Wash Reservoir, which provides more storage for the canals.

The Bureau of Land Management operates camping sites on the north and south shores of Senator Wash and at Xanyō Xamshré (a backwater of the river). It also operates a long-term campsite below the dam. Hidden Shores, a BLM concessionaire, is located on the east shore of the Imperial Reservoir.

• List of dams and reservoirs in California
• List of lakes of the Colorado Desert
• List of lakes in California

• "Imperial Diversion, California". FindLakes. 2009. Archived from the original on July 26, 2011. Retrieved September 22, 2009.
• Bureau of Reclamation (June 29, 2009). "Imperial Diversion Dam". U.S. Department of the Interior. Archived from the original on June 14, 2011. Retrieved September 22, 2009.

• Imperial Reservoir Watershed Map
• U.S. Geological Survey Geographic Names Information System: Imperial Reservoir