| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| O-Gelle,Stara Gala,Stará Gala,Ó-Gelle | city | Trnavsky | Slovakia | 47.99 | 17.48 | 403 | 6231 |
| Ohrady | city | Trnavsky | Slovakia | 47.98 | 17.70 | 370 | 6703 |
| Okoc | city | Trnavsky | Slovakia | 47.89 | 17.81 | 321 | 10170 |
| Ol'dza | city | Trnavsky | Slovakia | 48.09 | 17.42 | 830 | 7748 |
| Olgya | city | Trnavsky | Slovakia | 48.09 | 17.42 | 830 | 7748 |
| Ollé-Tejed | city | Trnavsky | Slovakia | 47.97 | 17.60 | 380 | 26077 |
| Opatovsky Sokolec | city | Trnavsky | Slovakia | 47.90 | 17.81 | 321 | 10265 |
| Opoj | city | Trnavsky | Slovakia | 48.30 | 17.64 | 416 | 17464 |
| Orechová Potôň | city | Trnavsky | Slovakia | 48.02 | 17.54 | 377 | 6614 |
| Oreske | city | Trnavsky | Slovakia | 48.74 | 17.31 | 1003 | 5627 |
| Ostrov | city | Trnavsky | Slovakia | 48.59 | 17.85 | 830 | 35502 |
| Ostrov | city | Trnavsky | Slovakia | 48.63 | 17.77 | 830 | 22878 |
| Osuské | city | Trnavsky | Slovakia | 48.62 | 17.44 | 830 | 4817 |
| Oľdza | city | Trnavsky | Slovakia | 48.09 | 17.42 | 830 | 7748 |