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 Range – which includes Colorado's highest peak, Mount Elbert – and carves the Black Canyon of the Gunnison before joining the Colorado. In the Grand Valley the Colorado becomes a meandering river in contrast to the steep mountain canyons above Grand Junction. It ranges from wide and from in depth with occasional deeper areas. From there the Colorado turns northwest, past Fruita and entering Ruby Canyon as it approaches the Colorado Plateau. It turns southwest once again just before entering Utah. In Utah the Colorado enters the high desert canyon country of the Colorado Plateau, flowing swiftly southwest through Westwater