| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Onga | city | Laanemaa | Estonia | 58.8225 | 23.7291667 | 19 | 880 |
| Ongassaare | city | Ida-Virumaa | Estonia | 59.1969444 | 27.4747222 | 209 | 4702 |
| Ongu | city | Hiiumaa | Estonia | 58.8505556 | 22.4663889 | 49 | 755 |
| Oniste | city | Viljandimaa | Estonia | 58.5072222 | 25.6475 | 275 | 1601 |
| Onniste | city | Viljandimaa | Estonia | 58.5072222 | 25.6475 | 275 | 1601 |
| Ontika | city | Ida-Virumaa | Estonia | 59.4347222 | 27.2911111 | 170 | 2832 |
| Ontika Asundus | city | Ida-Virumaa | Estonia | 59.4347222 | 27.2911111 | 170 | 2832 |
| Ontika-Saka | city | Ida-Virumaa | Estonia | 59.4338889 | 27.2463889 | 177 | 2734 |
| Onurme | city | Ida-Virumaa | Estonia | 59.1136111 | 26.9216667 | 200 | 4521 |
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