- Rackerby
- Rail Road Flat
- Raisin City
- Ramona
- Ranchita
- Rancho Bernardo
- Rancho Cordova
- Rancho Cucamonga
- Rancho Dominguez
- Rancho Mirage
- Rancho Murieta
- Rancho Palos Verdes
- Rancho Penasquitos
- Rancho San Diego
- Rancho Santa Fe
- Rancho Santa Margarita
- Ranchos Palos Verdes
- Randsburg
- Ravendale
- Raymond
- Red Bluff
- Redcrest
- Redding
- Redlands
- Redondo Beach
- Redondo Beach,
- Redway
- Redwood City
- Redwood Estates
- Redwood Valley
- Reedley
- Rescue
- Reseda
- Rialto
- Richardson Springs
- Richgrove
- Richmond
- Richvale
- Ridgecrest
- Rim Forest
- Rimforest
- Rio Dell
- Rio Linda
- Rio Nido
- Rio Oso
- Rio Vista
- Rio Vista Junction
- Ripley
- Ripon
- Riverbank
- Riverdale
- Riverside
- Robbins
- Rocklin
- Rodeo
- Rohnert Park
- Rolling Hills
- Rolling Hills Estates
- Romoland
- Rosamond
- Rosemead
- Roseville
- Roseville (granite Bay)
- Roseville,
- Ross
- Rough And Ready
- Round Mountain
- Rowland Heights
- Royal Oaks
- Rubidoux
- Rumsey
- Running Springs
- Rutherford
- Ryde