Big Bear Lake is a reservoir in the San Bernardino Mountains, in San Bernardino County, California, United States. It is a snow and rain fed lake, having no other means of tributaries or mechanical replenishment. At a surface elevation of 6,743 ft (2,055 m), it has an east-west length of approximately 7 mi (11 km) and is approximately 2.5 mi (4.0 km) at its widest measurement, though the lake's width mostly averages a little more than 1⁄2 mi (0.8 km). These approximations are based on the lake having an optimum retainable water level. At dam's end Big Bear measures its deepest water at 72 ft (22 m).