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
Steamboats of the Colorado River Mexico Territory, and Nevada state. They remained the primary means of transportation of freight until the advent of the more economical railroads began cutting away at their business from 1878 when the first line entered Arizona Territory. Steamboats were tried on the upper Colorado River: in Glen Canyon; on the Green River in Utah and Wyoming; and on the Grand River, (renamed as the upper part of the Colorado River after 1921), above its confluence with the Green River in Utah and in Colorado. These attempts in the late 19th Century and early 20th Century met with little success. The