Navajo Lake is a reservoir located in San Juan County and Rio Arriba County in northwestern New Mexico, in the southwestern United States. Portions of the reservoir extend into Archuleta County in southern Colorado. The lake is part of the Colorado River Storage Project, which here manages the upper reaches of the San Juan River, storing and releasing water that is used locally for irrigation, or ultimately reaching the Colorado River in Utah. Water is impounded in Navajo Lake by the earth- and rock-filled Navajo Dam, 3,800 feet (1,200 m) long and 400 feet (120 m) high, completed in 1962. The 15,600-acre (63 km2) lake is over 25 miles (40 km) long and lies at an elevation of up to 6,085 feet (1,855 m).