The dam on the Colorado River that created Lake Mead is Hoover Dam. Built in Black Canyon on the Arizona–Nevada border, it impounds the river to form the vast reservoir known as Lake Mead.
Construction took place during the 1930s as one of the most ambitious American public-works projects of the era. The dam was originally called Boulder Dam, but it was officially renamed Hoover Dam in 1947 after President Herbert Hoover, whose administration had supported the project. Its concrete arch-gravity design was an engineering landmark.
Lake Mead began filling in 1935 and became a crucial water source for Arizona, California and Nevada, as well as parts of Mexico. The dam also generates hydroelectric power and helps regulate Colorado River deliveries. A frequent mix-up is Glen Canyon Dam: it created Lake Powell upstream, while Hoover Dam created Lake Mead. At maximum capacity, Lake Mead stretches roughly 112 miles along the Colorado River.