Eldridge is a census-designated place (CDP) in Sonoma County, California, United States. The population was 1,233 at the 2010 census. It is notably the home to the Sonoma Developmental Center, the largest facility serving the needs of persons with developmental disabilities in the state.

The Sonoma Developmental Center (SDC) was a large state school in California, United States for people with developmental disabilities, and is located in Eldridge in Sonoma County. Former names for this hospital include California Home for the Care and Training of Feeble Minded Children (1883); Sonoma State Home (1909); Sonoma State Hospital (1953); and Sonoma Developmental Center starting in 1986. The center closed on 31 December 2018.