San Antonio Dam is an embankment flood control and debris dam on San Antonio Creek in San Bernardino County, California, about north of Ontario. The dam was authorized by the Flood Control Acts of 1936 and 1938 as part of a major program to provide flood protection in the Santa Ana River system. Construction began in April 1952 and finished in May 1956. The dam controls runoff from a rugged catchment area of in the San Gabriel Mountains.