Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. Originally known as Boulder Dam from 1933, it was officially renamed Hoover Dam by a joint resolution of Congress in 1947. The dam was named after President Herbert Hoover.
- Location: United States(Nevada/Arizona)
- Construction began: 1931
- Opening date: 1936
- Height: 726.4 ft (221.4 m)
- Length: 1,244 ft (379 m)
- Width (crest): 45 ft (14 m)