Big Bear Lake is a reservoir in the San Bernardino Mountains, in San Bernardino County, California, United States. It is a completely snow-fed lake, having no other means of tributaries or mechanical replenishment. At a surface elevation of , it has an east-west length of approximately and is approximately at its widest measurement, though the lake's width mostly averages a little more than . These approximations are based on the lake having an optimum retainable water level. At dam's end Big Bear measures its deepest water at .