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
Green River Crib Dam is about long, with a maximum height of , and spans the river in a semicircle open to the downstream side. The material of the dam mostly logs and rubble, with plank facing. The abutments of the dam are now a combination of stone and concrete, the wing wall on the east side extending downstream toward the bridge, where it formed part of the foundation of a now-destroyed mill. The earliest recorded documentation of a dam on this site dates to 1811, when Jonah Cutting is known to have a paper and linseed oil mill operating at the site. Some