Barrios de California O
- Oak Creek (29)
- Oak Grove (4)
- Oak Knoll Golf Links (2)
- Oak Knoll-Redwood Park (10)
- Oak Park (2)
- Oak Park (8)
- Oak Springs (2)
- Oak Valley Greens (3)
- Oak View (10)
- Oakmont (1)
- Oakmont Village (6)
- Oakridge (1)
- Ocean Beach (39)
- Ocean Crest (14)
- Ocean Hills (5)
- Ocean Park (75)
- Oceana (4)
- Oceanview (4)
- Ohlone (2)
- Oildale (7)
- Old Davis North (2)
- Old East Davis (3)
- Old Lakewood City (1)
- Old Las Palmas (3)
- Old Los Altos (3)
- Old Monterey (1)
- Old North Sacramento (6)
- Old Oakland (5)
- Old Palo Alto (1)
- Old Sacramento (5)
- Old San Leandro (15)
- Old Town (11)
- Old Town (5)
- Old Town Kern (1)
- Old Towne Orange (1)
- Old West Sacramento (1)
- Olde Torrance Neighborhood (15)
- Oleander/Sunset (30)
- Olinder (1)
- Olive Drive (2)
- Olive Drive Area (3)
- Olive Heights (5)
- Olivenhain (1)
- Olympia (5)
- Olympus Pointe (3)
- One Ford Road (3)
- Orange Park (1)
- Orangecrest (10)
- Orchard Hills (33)
- Orchard Park (3)
- Ord Grove (1)
- Orinda Oaks (1)
- Ortega Park (2)
- Oster (1)
- Otay Mesa (14)
- Otay Mesa West (8)
- Otay Ranch (66)
- Otay Ranch Village (20)
- Otay Town (8)
- Outer Arden-Arcade (128)
- Outer Campbell/Los Gatos (31)
- Outer Carmichael/Citrus Heights (72)
- Outer Ceres/Keyes (6)
- Outer Danville/San Ramon (62)
- Outer Davis (37)
- Outer East Bakersfield (31)
- Outer Elk Grove (46)
- Outer Folsom/Orangevale/Fair Oaks (29)
- Outer Lakeview (6)
- Outer Lompoc/Santa Ynez (4)
- Outer Mill Vly/Corte Madera/Sausalito (32)
- Outer Milpitas/Berryessa (24)
- Outer Mission (4)
- Outer Monterey (15)
- Outer Mountain View/Los Altos (74)
- Outer N Sac/Natomas/N Highlands (13)
- Outer Napa (9)
- Outer North San Jose (15)
- Outer NW Bakersfield (29)
- Outer Oxnard (7)
- Outer Rancho Cordova (45)
- Outer Richmond/Martinez (31)
- Outer Roseville/Rocklin (28)
- Outer San Jacinto (86)
- Outer San Rafael/Larkspur (13)
- Outer Santa Clara (149)
- Outer Santa Maria (4)
- Outer Santa Rosa (113)
- Outer Seaport (1)
- Outer Sunnyvale (18)
- Outer Sunset (13)
- Outer Thousand Oaks (110)
- Outer Walnut Creek (24)
- Outlying Palm Springs (246)
- Oxnard Dunes (3)
- Oxnard Shores (20)