| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Ora | city | California | United States | 36.15 | -120.33 | 830 | |
| Orange | city | California | United States | 33.79 | -117.85 | 196 | |
| Orange Avenue Junction | city | California | United States | 34.09 | -117.94 | 387 | |
| Orange Cove | city | California | United States | 36.62 | -119.31 | 830 | |
| Orange Mobile Home Park | city | California | United States | 33.83 | -117.83 | 341 | |
| Orange Park Acres | city | California | United States | 33.80 | -117.78 | 830 | |
| Orange Village Mobile Home Park | city | California | United States | 33.81 | -117.84 | 223 | |
| Orangetree | city | California | United States | 33.81 | -117.88 | 150 | |
| Orangevale | city | California | United States | 38.68 | -121.23 | 252 | |
| Orchams | city | California | United States | 34.48 | -119.88 | 396 | |
| Orchard | city | California | United States | 38.34 | -122.77 | 328 | |
| Orchard Lane Mobile Home Park | city | California | United States | 36.99 | -121.95 | 72 | |
| Orcutt | city | California | United States | 34.87 | -120.44 | 396 | |
| Ordbend | city | California | United States | 39.63 | -122.01 | 114 | |
| Ordway | city | California | United States | 34.00 | -117.17 | 1669 | |
| Ore'q (historical) | city | California | United States | 41.29 | -124.06 | 288 | |
| Oregon City | city | California | United States | 39.59 | -121.53 | 1197 | |
| Oregon House | city | California | United States | 39.36 | -121.28 | 1669 | |
| Orella (historical) | city | California | United States | 34.46 | -120.05 | 0 | |
| Orford | city | California | United States | 37.98 | -121.19 | 45 | |
| Orick | city | California | United States | 41.29 | -124.06 | 288 | |
| Orienta Losanĝeleso | city | California | United States | 34.02 | -118.17 | 187 | |
| Orinda | city | California | United States | 37.88 | -122.18 | 830 | |
| Orinda Village | city | California | United States | 37.89 | -122.20 | 830 | |
| Orion (historical) | city | California | United States | 36.31 | -119.74 | 196 | |
| Orita | city | California | United States | 32.98 | -115.41 | -1689 | |
| Orland | city | California | United States | 39.75 | -122.20 | 252 | |
| Orleans | city | California | United States | 41.30 | -123.54 | 859 | |
| Orleans Flat | city | California | United States | 39.43 | -120.83 | 4599 | |
| Orlem (historical) | city | California | United States | 36.19 | -119.05 | 830 | |
| Ormand | city | California | United States | 34.01 | -117.42 | 856 | |
| Oro Fino | city | California | United States | 41.58 | -122.92 | 2880 | |
| Oro Grande | city | California | United States | 34.60 | -117.33 | 2706 | |
| Oro Loma | city | California | United States | 36.89 | -120.69 | 177 | |
| Oroleve | city | California | United States | 39.53 | -121.18 | 3349 | |
| Orosi | city | California | United States | 36.54 | -119.29 | 347 | |
| Oroville | city | California | United States | 39.51 | -121.56 | 190 | |
| Oroville Junction | city | California | United States | 39.51 | -121.65 | 150 | |
| Orris | city | California | United States | 35.85 | -119.06 | 830 | |
| Orrs Springs | city | California | United States | 39.23 | -123.36 | 997 | |
| Ortega | city | California | United States | 37.90 | -121.27 | 16 | |
| Ortega | city | California | United States | 34.42 | -119.59 | 0 | |
| Ortonville | city | California | United States | 34.32 | -119.29 | 193 | |
| Orwood | city | California | United States | 37.94 | -121.57 | -1689 |