The St. Francis Dam, or the San Francisquito Dam, was a concrete gravity dam located in San Francisquito Canyon in northern Los Angeles County, California, United States, that was built between 1924 and 1926. The dam failed catastrophically in 1928, killing at least 431 people in the subsequent flood, in what is considered to have been one of the worst American civil engineering disasters of the 20th century and the third-greatest loss of life in California history.
View of the dam looking north, with water in its reservoir, in February 1927
A cross section view of the St Francis Dam after collapse
The approximate extent of the reservoir created by the dam
St. Francis Dam in February 1927
San Francisquito Canyon is a canyon created through erosion of the Sierra Pelona Mountains by the San Francisquito Creek, in Los Angeles County, Southern California.
San Francisquito Canyon is home to low-lying shrubs, dry grasses, and towering yucca that bloom during the spring.
Miners operating a hydraulic sluice at San Francisquito Canyon (c. 1890–1900).
Water held in a reservoir behind the St. Francis Dam in early 1927.
Looking upstream toward Green Valley from the St. Francis Dam ruins.
