| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Obberiya | city | Western Province | Sri Lanka | 7.2666667 | 79.8666667 | 19 | 68962 |
| Ogodapola | city | Western Province | Sri Lanka | 7.1 | 80.1 | 291 | 163471 |
| Okanduwa | city | Western Province | Sri Lanka | 6.7 | 80.0166667 | 180 | 88688 |
| Olabaduwa | city | Western Province | Sri Lanka | 6.7666667 | 80.0166667 | 269 | 219608 |
| Olaboduwa | city | Western Province | Sri Lanka | 6.7666667 | 80.0166667 | 269 | 219608 |
| Omatta | city | Western Province | Sri Lanka | 6.5666667 | 80.1833333 | 498 | 88694 |
| Opalla | city | Western Province | Sri Lanka | 6.7 | 80.1333333 | 446 | 86967 |
| Opata | city | Western Province | Sri Lanka | 7.1333333 | 79.9166667 | 19 | 169545 |
| Opatha | city | Western Province | Sri Lanka | 7.1333333 | 79.9166667 | 19 | 169545 |
| Opathella | city | Western Province | Sri Lanka | 7.0833333 | 80.0833333 | 295 | 169576 |
| Orutota | city | Western Province | Sri Lanka | 7.0833333 | 79.9833333 | 42 | 169576 |
| Oruwala | city | Western Province | Sri Lanka | 6.8833333 | 80 | 265 | 388255 |
| Oruwela | city | Western Province | Sri Lanka | 6.8833333 | 80 | 265 | 388255 |
| Owitigala | city | Western Province | Sri Lanka | 6.5 | 80.1166667 | 436 | 88730 |
| Owitigama | city | Western Province | Sri Lanka | 6.8333333 | 80.0333333 | 416 | 349302 |
| Owitigama | city | Western Province | Sri Lanka | 6.9666667 | 80.1166667 | 49 | 229608 |
| Owitiyagala | city | Western Province | Sri Lanka | 6.7333333 | 80.05 | 301 | 94503 |
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