Dam in the Black Canyon on the Colorado River between Nevada and Arizona, about 30 miles southeast of Las Vegas. It took 5 years to build, from 1931-1936. It is one of the largest dams in the world at 726 ft. (221 m) high and 1,244 ft. (379 m) long. It holds in the water which makes up Lake Mead. There are 4,360,000 cubic yards of concrete in the dam, powerplant, and appurtenant works, about 5 million barrels of cement. The hydroelectric capacity of Hoover Dam is 1,345 Mw.

The original name of the dam was Boulder Dam, because it was going to be built in Boulder canyon. After the planners saw that the Black Canyon was more suitable, they decided to build it there, but the name Canyon Dam stuck with it. In 1930 when construction was beginning, Interior Secretary Ray Wilbur said he would name it Hoover Dam, after the president Herbert Hoover. Many people were upset at naming it this, and argued to keep it as Boulder Dam. In 1933, the new Secretary of the Interior, Harold Ickes, said it would be named Boulder Dam, as originally planned. This name lasted until 1947, when a joint resolution of Congress permanently named it the Hoover Dam.