The Imperial Valley lies in California's Imperial County. It is located in southeastern Southern California, and is the site of an urban area largely centered on the city of El Centro. The Valley is bordered by the Colorado River to the east and, in part, the Salton Sea to the west. Farther west lies the San Diego and Imperial County border. To the north is the Inland Empire's Coachella Valley, which together form the Salton Trough, or the Cahuilla Basin, also the county line of Imperial and Riverside counties, and to the south the international boundary with the U.S.