Glen Canyon Dam is a concrete arch-gravity dam on the Colorado River in northern Arizona, United States, near the town of Page. The 220 m (710-foot high dam was built from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of 33 cubic-km (27 million acre feet).The dam is named for Glen Canyon, a series of deep sandstone gorges now flooded by the reservoir.