Course of the Colorado River into the Virgin River, which ran southward through what is now Overton Arm to join the Colorado River near the now-ghost town of St. Thomas, Nevada. At Hoover Dam, the Colorado turns due south through Black Canyon, a direction it will follow for the remainder of its course to the Gulf of California. It passes under the Mike O'Callaghan–Pat Tillman Memorial Bridge (Hoover Dam Bypass), the highest concrete arch bridge in the world, carrying U.S. Route 93 at a height of above the Colorado River. At the end of Black Canyon the Colorado widens into Lake Mohave, created by the
Steamboats of the Colorado River the river, except for the "Searchlight" that lingered on as property of the U. S. Reclamation Service until it was sunk in 1916. Steamboats were tried in Glen Canyon, the Green River in Utah and Wyoming and the Grand River, (after 1921 renamed as the upper part of the Colorado River), above its confluence with the Green River in Utah and in Colorado. Unlike the Lower Colorado, the railroads made possible most of this steam navigation on the Upper Colorado, bringing in the boats or their parts and their fuel to the points on the river where they were assembled