Morris Dam (officially the Samuel B. Morris Dam) is a concrete gravity dam across the San Gabriel River in the U.S. state of California. 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. Situated in northern Los Angeles County, the dam impounds the 417-acre (169 ha) Morris Reservoir in the Angeles National Forest, a few miles northeast of Azusa. From the 1940s to the 1990s, the reservoir was also used for underwater missile testing by the United States military.
This dam sits south of Silver Mountain and north of Glendora Ridge, which flank the spectacular 1,500-foot (460 m) deep San Gabriel Canyon. It is roughly 37 miles (60 km) upstream of the San Gabriel's mouth on the Pacific Ocean and 6 miles (9.7 km) downstream of the river's beginning at the confluence of its East and West Forks. The 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). The dam's crest itself is at an elevation of 1,161 feet (354 m).