Boulder Canyon (Colorado River) Boulder Canyon (Colorado River) Boulder Canyon, originally Devils Gate Canyon, is a canyon on the Colorado River, above Hoover Dam, now flooded by Lake Mead. It lies between Clark County, Nevada and Mohave County, Arizona. It heads at western end of the Virgin River Basin of Lake Mead, at about . Boulder Canyon divides the Black Mountains into the Black Mountains of Arizona, and the Black Mountains of Nevada. Its mouth is now under the eastern end of the Boulder Basin of Lake Mead, between Canyon Point in Nevada and Canyon Ridge in Arizona. Its original mouth is now underneath
Colorado City, Nevada Colorado City, Nevada Colorado City is now a ghost town, in Clark County, Nevada, located under Lake Mohave at the mouth of El Dorado Canyon. Colorado City was a mining camp in the Colorado Mining District (New Mexico Territory) and a steamboat landing at the mouth of the El Dorado Canyon on the Colorado River, for shipments via steamboats of the Colorado River. Founded in 1861, Colorado City, was at first located in New Mexico Territory, until 1863, when it became part of Mohave County of Arizona Territory. In 1867 it became part of Lincoln County in the state of