Morris Reservoir is located in the San Gabriel Mountains within Angeles National Forest, approximately 5 miles north of Azusa, California. The reservoir, created by Morris Dam in 1935, sits at an elevation of about 1,100 feet.

IMPORTANT NOTICE: Paddling and all water recreation is prohibited on Morris Reservoir. The site formerly served as a naval weapons test facility from World War II through the 1990s, and while it was transferred to the Los Angeles County Department of Public Works in 1995, public access remains restricted. The area is actively patrolled both by ground units and helicopter surveillance, with significant fines imposed for violations.

The reservoir extends along California State Route 39 and is situated just downstream from San Gabriel Dam. The 245-foot gravity dam creates a substantial impoundment that served historically as a testing ground for submarine-based warfare systems, torpedoes, and the Polaris missile program. While most testing facility buildings have been removed as part of restoration efforts, the site's military legacy continues to impact public access.

The surrounding landscape features the characteristic steep terrain of the San Gabriel Mountains. While the reservoir itself is off-limits, the surrounding area is notable for its position within the Angeles National Forest ecosystem. The site is undergoing restoration to return it to a more natural state, though timeline and future public access plans remain unclear.

Given the strict prohibition on water access and the serious enforcement measures in place, paddlers should instead consider nearby alternatives such as Puddingstone Reservoir in San Dimas, which offers designated launch areas and permitted water recreation.