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 of this water is used for irrigation in the Mexicali Valley, one of Mexico's most fertile agricultural regions. Below the Morelos Dam the Colorado forms the international border for a short distance, between Baja California and Arizona, before reaching the Southern International Boundary at San Luis Rio Colorado, where it crosses entirely into Mexico. For the remainder of its course to the Gulf, the river forms the boundary between Baja California (west) and Sonora (east). "River", however, is a misnomer as the Colorado is dry or small stream most of the year, due to its flow being almost completely exhausted