Traveling from Las Vegas to Utah? Visit the largest reservoir in the United States, Hoover Dam. Hoover Dam is located on the border of Nevada and Arizona. The dam was originally opened in 1936. The dam sits in the Black Canyon of the Colorado River. Hoover Dam impounds Lake Mead and is managed by the Bureau of Reclamation. Whether you want to make a quick stop or schedule a tour this architectural feat is beautiful and worth the stop. The Mike O’Callaghan-Pat Tillman Memorial Bridge is the world’s tallest concrete arch bridge and towers 880 feet over the dam providing terrific views. The bridge connects Nevada and Arizona and allows for a good photo opportunity standing in both states.