- Novato
- Nubieber
- Nuevo
- O Neals
- Oak Park
- Oak Run
- Oak View
- Oakdale
- Oakhurst
- Oakland
- Oakley
- Oakville
- Obrien
- Occidental
- Oceano
- Oceanside
- Ocotillo
- Ojai
- Olancha
- Old Station
- Olema
- Olivehurst
- Olympic Valley
- Ontario
- Onyx
- Orange
- Orange Cove
- Orangevale
- Oregon House
- Orick
- Orinda
- Orland
- Orleans
- Oro Grande
- Orosi
- Oroville
- Oxnard
- Pacific Grove
- Pacific Palisades
- Pacifica
- Pacoima
- Paicines
- Pala
- Palermo
- Palm Desert
- Palm Springs
- Palmdale
- Palo Alto
- Palo Cedro
- Palo Verde
- Palomar Mountain
- Palos Verdes Peninsula
- Panorama City
- Paradise
- Paramount
- Parker Dam
- Parlier
- Pasadena
- Paskenta
- Paso Robles
- Patterson
- Patton
- Pauma Valley
- Paynes Creek
- Pearblossom
- Pebble Beach
- Penn Valley
- Penngrove
- Penryn
- Perris
- Pescadero
- Petaluma
- Petrolia
- Phelan
- Phillipsville
- Philo
- Pico Rivera
- Piedmont
- Piedra
- Piercy
- Pilot Hill
- Pine Grove
- Pine Mountain Club
- Pine Valley
- Pinecrest
- Pinole
- Pinon Hills
- Pioneer
- Pioneertown
- Piru
- Pismo Beach
- Pittsburg
- Pixley
- Placentia
- Placerville
- Planada
- Platina
- Playa Vista
- Pleasant Grove
- Pleasant Hill
- Pleasanton
- Plymouth
- Point Arena
- Point Reyes Station
- Pollock Pines
- Pomona
- Pope Valley
- Port Costa
- Port Hueneme
- Porter Ranch
- Porterville
- Portola
- Portola Valley
- Posey
- Potrero
- Potter Valley
- Poway
- Prather
- Princeton
- Proberta
- Quincy
- Rackerby
- Rail Road Flat
- Raisin City
- Ramona
- Ranchita
- Rancho Cordova
- Rancho Cucamonga
- Rancho Mirage
- Rancho Palos Verdes
- Rancho Santa Fe
- Rancho Santa Margarita
- Randsburg
- Ravendale
- Raymond
- Red Bluff
- Red Mountain
- Redcrest
- Redding
- Redlands
- Redondo Beach
- Redway
- Redwood City
- Redwood Estates
- Redwood Valley
- Reedley
- Represa
- Rescue
- Reseda
- Rialto