- Randall Island
- Río Linda
- River Oaks
- Ragtown
- Rainbow Wells
- Ranchos del Oro
- Renoville
- Rimrock
- Rancho Del Campo
- Ridgecrest Estates
- Rincon
- Riverview
- Rosemont
- Roberts Island
- Roma
- Rough and Ready Island
- Rancho del Arroyo Mobile Home Park
- Reeves Place
- Renshaw Place
- Ravenswood
- Redwood Junction
- Redwood Park
- Rex
- Rosemary
- Rinconada
- Rucker
- Redwood Grove
- Redwood Lodge
- Rices Junction
- Rincon