- Shasta
- Sheep Ranch
- Sheridan
- Sherman Oaks
- Shively
- Shore Acres
- Sierra City
- Sierraville
- Silverado
- Sky Londa
- Skyforest
- Sleepy Hollow
- Sleepy Hollow, San Bernardino
- Sloat
- Sloughhouse
- Smartsville
- Smiley Park
- Smith River
- Snelling
- Soda Springs
- Solromar
- Somerset
- Somes Bar
- Somis
- South Fontana
- South Laguna
- South Santa Rosa
- Standard
- Standish
- Stirling City