Glen Canyon Dam is immense. It rises 710 feet above the Colorado River bedrock with a 1,560 foot long crest. It is 300 feet thick at the base and holds back some 9 trillion gallons of water. Completed in 1963, Lake Powell only reached its full level 17 years later in 1980. ..The Carl Hayden Visitor Center at the dam provides information about the dam (and Lake Powell). It is opened every day from 8 to 5 except Christmas and New Years Day, with extended hours in summer. Both guided and self-guided tours can be taken.
The Glen Canyon Dam is located just south of the Utah/Arizona border where Hwy. 89 crosses the Colorado River. It is about 2 miles north of Page, Arizona. (The bridge crosses 700 feet above the river and is the second highest bridge in the country.)