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
The Exploration of the Colorado River and Its Canyons The Exploration of the Colorado River and Its Canyons The Exploration of the Colorado River and Its Canyons by John Wesley Powell is a classic of American exploration literature. It is about the Powell Geographic Expedition of 1869 which was the first trip down the Colorado River by boat, including the first trip through the Grand Canyon. Powell's first written accounts of his exploration appeared in the January, February and March 1875 editions of "Scribner’s Monthly" as "The Canons of the Colorado". The Smithsonian published it in book form in 1875 under title "Report of the Exploration of the Colorado