Crowley Lake, Water reservoir in Mono County, California.

Crowley Lake is a reservoir on the upper Owens River in southern Mono County, California, 15 miles south of Mammoth Lakes. Long Valley Dam, 126 feet high, impounds 183,465 acre-feet of water. The lake lies at 2,063 meters and is bordered by dry shoreline and a snow-patched mountain range.

The Los Angeles Department of Water and Power built Long Valley Dam in 1941 to create this reservoir for the Los Angeles Aqueduct system. The project was designed to secure water supply for the growing city.

The water body takes its name from Father John J. Crowley, a priest who worked to bring visitors to Owens Valley in the 1930s. His efforts helped the region welcome travelers before his death in 1940.

Crowley Lake Fish Camp on the shore provides the only access to the water with boat rentals and camping areas. The facility supplies anglers with everything needed for a day on the water.

The columns along the eastern shore were explained in 2015 by UC Berkeley geologists: snowmelt trapped under hot ash from the Long Valley Caldera rose as steam, depositing erosion-resistant minerals. Nearly 5,000 pillars, some 20 feet tall and linked by arches, stand across 4,000 acres.