Glen Canyon Dam is a concrete arch-gravity dam on the Colorado River in northern Arizona, United States, near the town of Page. The 710-foot high dam was built by the U.S. Bureau of Reclamation from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of 27 million acre-feet. The dam is named for Glen Canyon, a series of deep sandstone gorges now flooded by the reservoir; Lake Powell is named for John Wesley Powell, who in 1869 led the first expedition to traverse the Colorado's Grand Canyon by boat.
A dam in Glen Canyon was studied as early as 1924, but these plans were initially dropped in favor of the Hoover Dam which was located in the Black Canyon. By the 1950s, due to rapid population growth in the seven U.S. and two Mexican states comprising the Colorado River Basin, the Bureau of Reclamation deemed the construction of additional reservoirs necessary. Contrary to popular belief, Lake Powell was not the result of negotiations over the controversial damming of the Green River within Dinosaur National Monument at Echo Park; the Echo Park Dam proposal was abandoned due to nationwide citizen pressure on Congress to do so.