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
Ice Harbor Dam security, visitors must pass through the security gate to gain access. Lake Sacajawea, named for Sacajawea, is formed behind the dam. The lake stretches to the base of Lower Monumental Dam, upstream. The Wallula Channel, formed from the backup of Snake River entering the Columbia River just southeast of Pasco, runs downstream from the base of the dam. The highest temperature ever measured in Washington state, at , was recorded at Ice Harbor Dam on August 5, 1961. Ice Harbor Dam Ice Harbor Lock and Dam is a hydroelectric, concrete gravity run-of-the-river dam on the Snake River in Walla Walla