Hoover Dam in Black Canyon

Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River. It sits on the boundary between Nevada and Arizona.

Construction began in 1931 and finished in 1936—two years early.

The Boulder Canyon Project Act funded the dam construction.

The wedge-shaped wall is 660 feet thick at the bottom, narrowing to 45 feet near the top.

U.S. Route 93 ran along the crest until October 2010. Seven million tourists visit yearly.

Generators provide power for utilities serving customers in Nevada, Arizona, and California.

Congress named it Hoover Dam, but the Roosevelt administration called it Boulder Dam. Congress restored the name Hoover Dam in 1947.