Barrios de California O
- Oak Creek (16)
- Oak Grove (2)
- Oak Grove Manor (1)
- Oak Knoll (1)
- Oak Knoll-Redwood Park (7)
- Oak Park (1)
- Oak Park (11)
- Oak Valley Greens (3)
- Oak View (10)
- Oakmont (1)
- Oakmont Village (9)
- Oakridge (1)
- Ocean Beach (46)
- Ocean Crest (11)
- Ocean Hills (7)
- Ocean Park (71)
- Oceana (9)
- Oceanview (8)
- Ohlone (1)
- Oildale (4)
- Old Agoura (1)
- Old Davis North (1)
- Old East Davis (3)
- Old Las Palmas (4)
- Old Los Altos (2)
- Old North Sacramento (6)
- Old Oakland (3)
- Old Palo Alto (2)
- Old Sacramento (3)
- Old San Leandro (12)
- Old Town (13)
- Old Town (3)
- Old Town Kern (5)
- Old Towne Orange (2)
- Old West Sacramento (3)
- Olde Torrance Neighborhood (20)
- Oleander/Sunset (23)
- Olive Drive (2)
- Olive Drive Area (3)
- Olive Heights (8)
- Olivenhain (1)
- Olympia (5)
- Olympus Pointe (2)
- One Ford Road (3)
- Orange Park (1)
- Orangecrest (7)
- Orchard Hills (34)
- Orchard Park (3)
- Ord Grove (2)
- Ortega Park (1)
- Otay Mesa (10)
- Otay Mesa West (6)
- Otay Ranch (58)
- Otay Ranch Village (12)
- Otay Town (6)
- Outer Arden-Arcade (123)
- Outer Campbell/Los Gatos (25)
- Outer Carmichael/Citrus Heights (64)
- Outer Ceres/Keyes (5)
- Outer Danville/San Ramon (64)
- Outer Davis (39)
- Outer East Bakersfield (30)
- Outer Elk Grove (41)
- Outer Folsom/Orangevale/Fair Oaks (34)
- Outer Lakeview (7)
- Outer Lompoc/Santa Ynez (4)
- Outer Mill Vly/Corte Madera/Sausalito (19)
- Outer Milpitas/Berryessa (19)
- Outer Mission (3)
- Outer Monterey (11)
- Outer Mountain View/Los Altos (89)
- Outer N Sac/Natomas/N Highlands (9)
- Outer Napa (11)
- Outer North San Jose (14)
- Outer NW Bakersfield (28)
- Outer Oxnard (5)
- Outer Palo Alto (1)
- Outer Rancho Cordova (49)
- Outer Richmond/Martinez (26)
- Outer Roseville/Rocklin (33)
- Outer San Jacinto (87)
- Outer San Rafael/Larkspur (8)
- Outer Santa Clara (137)
- Outer Santa Maria (2)
- Outer Santa Rosa (87)
- Outer Sunnyvale (20)
- Outer Sunset (5)
- Outer Thousand Oaks (96)
- Outer Walnut Creek (34)
- Outlying Palm Springs (243)
- Overfelt (1)
- Oxnard Dunes (3)
- Oxnard Shores (21)