[1] The reservoir is located alongside California State Route 39, approximately 5 miles (8.0 km) north of the city of Azusa.

[2] The reservoir was transferred to the Los Angeles County Department of Public Works in 1995.

The test facility was established by Caltech, which was developing weapons for the Navy at its Naval Ordnance Test Station (NOTS) at China Lake (town), near Ridgecrest, California.

Because China Lake is a dry lake in the Mojave Desert, Caltech opened this substation at the Morris Reservoir, near their campus, north of Azusa in the San Gabriel Mountains.

This site was used especially for the development of submarine-based warfare systems, including torpedoes, bombs, and submarine-launched missiles like the Polaris rocket, the first ballistic missile that could be launched from submerged submarines.