- Ross
- Russian River Terrace
- Rancho Tehama Reserve
- Rawson
- Red Bank
- Richfield
- Roberts Place
- Rosewood
- Ridgeville
- Ridgeville Islands
- Russ Place
- Rabbit Island
- Radnor
- Rayo
- Rector
- Red Fir
- Redbanks
- Redwood Corral
- Roche
- Rocky Hill
- Rodriguez Camp
- Ralph
- Rancho Poquitos
- Rancho Sonora Estates
- Rawhide
- Rolling Hills
- Rail Road Flat
- Rainbow
- Raisin City
- Ramona