Lake Eleanor is a reservoir located in Yosemite National Park at an altitude of 4,657 feet (1,419 m). The reservoir has a capacity of 26,100 acre feet (32,000,000 m³) and a surface area of 953 acres (3.9 km²). The lake was formed in 1918 by damming Eleanor Creek as part of the Hetch Hetchy reservoir system, constructed to supply water and power to the city of San Francisco.