Barrios de California O
- Oak Creek (22)
- Oak Grove (2)
- Oak Grove Manor (1)
- Oak Knoll Golf Links (1)
- Oak Knoll-Redwood Park (5)
- Oak Park (9)
- Oak Springs (2)
- Oak Valley Greens (1)
- Oak View (3)
- Oakmont (1)
- Oakmont Village (8)
- Ocala (2)
- Ocean Beach (28)
- Ocean Crest (15)
- Ocean Hills (5)
- Ocean Park (58)
- Oceana (10)
- Oceanview (4)
- Ohlone (1)
- Oildale (2)
- Old East Davis (2)
- Old Las Palmas (3)
- Old Los Altos (1)
- Old North Sacramento (8)
- Old Oakland (4)
- Old Sacramento (2)
- Old San Leandro (14)
- Old Town (11)
- Old Town (2)
- Old Town Kern (1)
- Old West Sacramento (4)
- Olde Torrance Neighborhood (18)
- Oleander/Sunset (20)
- Olive Drive (2)
- Olive Drive Area (7)
- Olive Heights (7)
- Olympia (2)
- Olympus Pointe (1)
- One Ford Road (3)
- Orange Heights (1)
- Orange Park (1)
- Orangecrest (7)
- Orchard Hills (25)
- Orchard Park (2)
- Ortega Park (2)
- Otay Mesa (10)
- Otay Mesa West (13)
- Otay Ranch (53)
- Otay Ranch Village (10)
- Otay Town (5)
- Outer Arden-Arcade (95)
- Outer Campbell/Los Gatos (50)
- Outer Carmichael/Citrus Heights (70)
- Outer Ceres/Keyes (3)
- Outer Danville/San Ramon (46)
- Outer Davis (22)
- Outer East Bakersfield (38)
- Outer Elk Grove (38)
- Outer Folsom/Orangevale/Fair Oaks (49)
- Outer Lakeview (7)
- Outer Lompoc/Santa Ynez (2)
- Outer Mill Vly/Corte Madera/Sausalito (20)
- Outer Milpitas/Berryessa (21)
- Outer Mission (3)
- Outer Monterey (12)
- Outer Mountain View/Los Altos (137)
- Outer N Sac/Natomas/N Highlands (14)
- Outer Napa (13)
- Outer North San Jose (15)
- Outer NW Bakersfield (32)
- Outer Oxnard (4)
- Outer Rancho Cordova (53)
- Outer Richmond/Martinez (18)
- Outer Roseville/Rocklin (28)
- Outer San Jacinto (109)
- Outer San Rafael/Larkspur (8)
- Outer Santa Clara (117)
- Outer Santa Maria (8)
- Outer Santa Rosa (75)
- Outer Sunnyvale (17)
- Outer Sunset (6)
- Outer Thousand Oaks (105)
- Outer Walnut Creek (79)
- Outlying Palm Springs (209)
- Oxnard Dunes (3)
- Oxnard Shores (26)