Boulder Canyon (Colorado River) steamboats as they passed over the dangerous rapids of Devil's Gate Canyon, during their high water runs to the mouth of the Virgin River at Rioville, Nevada. 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
Canyon Lake (Arizona) Canyon Lake (Arizona) Canyon Lake is one of four reservoirs that were formed by the damming of the Salt River in the U.S. state of Arizona. The lake was formed by the Mormon Flat Dam, which was completed in 1925 after two years of construction. Canyon Lake, with a surface area of , is the third and smallest of four lakes created along the Salt River. Two others, Apache Lake and Roosevelt Lake, are upstream. The fourth, Saguaro Lake, is downstream. Canyon Lake lies approximately up the Apache Trail from Apache Junction, Arizona and east of Phoenix. It is within