what state is hoover dam
Hoover Dam. Hoover Dam, formerly called Boulder Dam, dam in Black Canyon on the Colorado River, at the Arizona-Nevada border, U.S. Constructed between 1930 and 1936, it is the highest concrete arch dam in the United States. It impounds Lake Mead, which extends for 115 miles (185 km) upstream and is one of the largest manmade lakes in the world.