Black Canyon of the Colorado Black Canyon of the Colorado The Black Canyon of the Colorado is the canyon on the Colorado River where Hoover Dam was built. The canyon is located on the Colorado River at the state line between Nevada and Arizona. The western wall of the gorge is in the El Dorado Mountains, and the eastern wall is in the Black Mountains of Arizona. The canyon formed about 15 million years ago during the Miocene Basin and Range uplift. Black Canyon gets its name from the black volcanic rocks that are found throughout the area. Just south of the Hoover Dam on
Course of the Colorado River Topock Marsh in Topock Gorge and widens into Lake Havasu, formed by Parker Dam. Lake Havasu provides recreation as well as the home of the retired U.K. London Bridge in Lake Havasu City, Arizona, now the New London Bridge. Near Parker Dam are the first two major diversions of the lower Colorado: the Colorado River Aqueduct, which travels west to Los Angeles and San Diego, California; and the Central Arizona Project, which sends water east towards Phoenix and Tucson, Arizona. The intermittent Bill Williams River joins the Colorado from the east in Lake Havasu, just above Parker Dam. The river