Sweetwater Reservoir is a 960-acre (390 ha) artificial lake in San Diego County, California, formed by Sweetwater Dam on the Sweetwater River.

The area surrounding the reservoir is home to several species, including least Bell's vireo and the California gnatcatcher.

It lies near the census-designated places of Bonita, La Presa and Spring Valley.

The drainage basin it forms along with Loveland Reservoir covers 230 square miles (600 km2).

This San Diego County, California–related article is a stub.