Imperial Valley

Imperial Valley, valley, southeastern California, bounded by the Salton Sea on the north, the Chocolate Mountains on the east, and desert ranges on the west. The valley, crossed by the border between the United States and Mexico, is part of a larger valley that extends south into Mexico; the Mexican section is called Mexicali Valley. Lying below sea level, and formerly arid desert, the valley is now one of the richest agricultural areas in the world and the largest year-round irrigated agricultural area in North America as a result of irrigation by waters of the Colorado River. Truck farming and dairying are important; chief crops include melons, citrus and other fruits, lettuce and other vegetables, alfalfa, barley, and cotton. Much of the manual labor in the valley is performed by migrant workers. Principal cities include Brawley, Calexico, and El Centro.

The first waters from the Colorado were brought in through the Imperial Canal, opened in 1901. The same source was tapped for the All-American Canal, completed in 1940 as part of the Hoover Dam irrigation system built by the U.S. government. This canal, which is 130 km (80 mi) long and 60 m (200 ft) wide, is the largest irrigation canal in the U.S. and supplies most of the water for the farmland in the Imperial Valley.