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
John Day Dam John Day Dam The John Day Dam is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift (110 feet) of any U.S. lock. The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4 miles (123 kilometers) up the river channel to the foot of the McNary Dam. John Day Dam is part of the Columbia River Basin system of dams. John Day Dam is located 28 miles (45 km) east of the