| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Oasi dei Due Mari | city | Sardegna | Italy | 39.1294444 | 9.5075 | 127 | 7996 |
| Olbia | city | Sardegna | Italy | 40.9166667 | 9.5166667 | 0 | 6140 |
| Olia Speciosa | city | Sardegna | Italy | 39.2780556 | 9.525 | 209 | 12542 |
| Ollastra Simaxis | city | Sardegna | Italy | 39.9522222 | 8.7341667 | 193 | 6966 |
| Ollastra Usellus | city | Sardegna | Italy | 39.7869444 | 8.8644444 | 918 | 6930 |
| Olìa Speciosa | city | Sardegna | Italy | 39.2780556 | 9.525 | 209 | 12542 |
| Oristano | city | Sardegna | Italy | 39.9030556 | 8.5919444 | 49 | 6835 |
| Orroli | city | Sardegna | Italy | 39.6930556 | 9.2513889 | 1988 | 4480 |
| Ortacesus | city | Sardegna | Italy | 39.5391667 | 9.0833333 | 551 | 12887 |
| Orti su Loi | city | Sardegna | Italy | 39.1286111 | 9.091667 | 0 | 753 |
| Osini | city | Sardegna | Italy | 39.8283333 | 9.4922222 | 1640 | 4470 |
| Ozieri | city | Sardegna | Italy | 40.5833333 | 9 | 1443 | 6973 |
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