The dam was built in the 1930s as a water supply facility for the city of Pasadena, but is now mostly utilized for flood control and flow regulation for groundwater recharge.

This dam sits south of Silver Mountain and north of Glendora Ridge, which flank the 1,500-foot (460 m) deep San Gabriel Canyon.

[1] Morris Reservoir is about 3 miles (4.8 km) long and 1,152 feet (351 m) above sea level at maximum pool, covering 417 acres (169 ha).

[8] In 1935, contrary to its original purpose, Morris Dam was sold to the Metropolitan Water District of Southern California (MWD), which owned it through most of the 20th century.

[11] In 1995, MWD sold the dam to the Los Angeles County Department of Public Works, which continues to operate it and the reservoir today.