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
Transportation in Arizona large-scale reconstruction and expansion of I-10 was supported and completed in mid-2009. Yuma is served by I-8, while Casa Grande served by I-8 and I-10; Flagstaff is served by I-17 and I-40. US 95 parallels the Colorado River, from Las Vegas to the Mexico–United States border near Yuma. Historic US 66, a major route for Midwestern emigrants prior to the advent of the interstate highway system, traversed the northern part of the state, passing through Flagstaff and Kingman. US 66 in Arizona closely followed the route of what is now I-40 except for an stretch between Seligman and Kingman now