Barrios de California O
- Oak Creek (22)
- Oak Grove (1)
- Oak Grove Manor (1)
- Oak Knoll (2)
- Oak Knoll-Redwood Park (4)
- Oak Park (10)
- Oak Springs (1)
- Oak Valley Greens (2)
- Oak View (7)
- Oakmont (1)
- Oakmont Village (9)
- Oakridge (2)
- Ocean Beach (53)
- Ocean Crest (12)
- Ocean Hills (7)
- Ocean Park (63)
- Oceana (7)
- Oceanview (3)
- Ohlone (2)
- Oildale (2)
- Old Davis North (1)
- Old East Davis (3)
- Old Las Palmas (4)
- Old Los Altos (3)
- Old North Sacramento (9)
- Old Oakland (4)
- Old Palo Alto (2)
- Old Sacramento (5)
- Old San Leandro (12)
- Old Town (12)
- Old Town (2)
- Old Town Kern (7)
- Old Towne Orange (2)
- Old West Sacramento (2)
- Olde Torrance Neighborhood (19)
- Oleander/Sunset (24)
- Olive Drive (2)
- Olive Drive Area (4)
- Olive Heights (9)
- Olympia (3)
- Olympus Pointe (2)
- One Ford Road (2)
- Orange Park (2)
- Orangecrest (2)
- Orchard Hills (33)
- Orchard Park (2)
- Ord Grove (2)
- Ortega Park (1)
- Oster (1)
- Otay Mesa (11)
- Otay Mesa West (7)
- Otay Ranch (61)
- Otay Ranch Village (8)
- Otay Town (6)
- Outer Arden-Arcade (126)
- Outer Campbell/Los Gatos (25)
- Outer Carmichael/Citrus Heights (63)
- Outer Ceres/Keyes (4)
- Outer Danville/San Ramon (53)
- Outer Davis (31)
- Outer East Bakersfield (37)
- Outer Elk Grove (34)
- Outer Folsom/Orangevale/Fair Oaks (36)
- Outer Lakeview (8)
- Outer Lompoc/Santa Ynez (3)
- Outer Mill Vly/Corte Madera/Sausalito (19)
- Outer Milpitas/Berryessa (18)
- Outer Mission (2)
- Outer Monterey (13)
- Outer Mountain View/Los Altos (92)
- Outer N Sac/Natomas/N Highlands (11)
- Outer Napa (9)
- Outer North San Jose (15)
- Outer NW Bakersfield (22)
- Outer Oxnard (4)
- Outer Palo Alto (1)
- Outer Rancho Cordova (49)
- Outer Richmond/Martinez (24)
- Outer Roseville/Rocklin (30)
- Outer San Jacinto (89)
- Outer San Rafael/Larkspur (6)
- Outer Santa Clara (129)
- Outer Santa Maria (3)
- Outer Santa Rosa (80)
- Outer Sunnyvale (21)
- Outer Sunset (11)
- Outer Thousand Oaks (83)
- Outer Walnut Creek (30)
- Outlying Palm Springs (234)
- Oxnard Dunes (3)
- Oxnard Shores (23)