| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Opal Cliff Park Mobile Home Park | city | California | United States | 36.96 | -121.97 | 29 | |
| Opal Cliffs | city | California | United States | 36.96 | -121.96 | 0 | |
| Opegoi (historical) | city | California | United States | 41.26 | -123.61 | 1013 | |
| Opera Plaza | city | California | United States | 37.78 | -122.42 | 160 | |
| Ophir | city | California | United States | 38.89 | -121.12 | 830 | |
| Ophir Hill Acres | city | California | United States | 39.19 | -121.04 | 3349 |