Hoover Dam the change, stating, "I didn't know Hoover was that small a man to take credit for something he had nothing to do with." Hoover Dam was recognized as a National Civil Engineering Landmark in 1984. It was listed on the National Register of Historic Places in 1981, and was designated a National Historic Landmark in 1985, cited for its engineering innovations. Other sources Hoover Dam 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. It was constructed between 1931 and 1936 during the
Course of the Colorado River most difficult rapids. At Hite the Hite Crossing Bridge – the only bridge over the Colorado for nearly – carries Utah State Route 95 over the river. Below here the Colorado is joined by the Dirty Devil River and begins to widen into Lake Powell, the giant reservoir formed by Glen Canyon Dam downstream. Lake Powell, a popular houseboating destination, is surrounded by the Glen Canyon National Recreation Area and receives over 2 million visitors each year despite its remote location. Before the dam was completed in 1966 the Colorado flowed through Glen Canyon, a sandstone gorge known for its