The St. Francis Dam was a curved concrete gravity dam, designed to create a reservoir as a storage point of the Los Angeles Aqueduct. It was located in San Francisquito Canyon of the Sierra Pelona Mountains, about 40 miles (64km) northwest of Los Angeles, California, approximately 10 miles (16km) north of the city of Santa Clarita.
The dam was designed and built between 1924 and 1926 by the Los Angeles Department of Water and Power, then named the Bureau of Water Works and Supply. The department was under the supervision of the city's chief engineer William Mulholland.
At two and a half minutes before midnight on March 12, 1928 the dam failed catastrophically and the resus