| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Obdokovská Pusta | city | Nitriansky | Slovakia | 48.50 | 18.05 | 830 | 7152 |
| Obid | city | Nitriansky | Slovakia | 47.78 | 18.65 | 357 | 17166 |
| Obsolovce | city | Nitriansky | Slovakia | 48.50 | 18.01 | 830 | 5609 |
| Obyce | city | Nitriansky | Slovakia | 48.43 | 18.46 | 1669 | 9919 |
| Ockov | city | Nitriansky | Slovakia | 48.65 | 17.77 | 830 | 13101 |
| Ogyalla,Stara ďala,Stará ďala,Ógyalla | city | Nitriansky | Slovakia | 47.88 | 18.20 | 830 | 10316 |
| Ohaj | city | Nitriansky | Slovakia | 48.08 | 18.25 | 830 | 11660 |
| Okoličná na Ostrove | city | Nitriansky | Slovakia | 47.80 | 17.92 | 337 | 5259 |
| Okrut | city | Nitriansky | Slovakia | 49.15 | 18.38 | 1213 | 22926 |
| Okánikov | city | Nitriansky | Slovakia | 47.78 | 17.88 | 337 | 5203 |
| Olichov | city | Nitriansky | Slovakia | 48.36 | 18.47 | 925 | 8481 |
| Olvar | city | Nitriansky | Slovakia | 48.10 | 19.02 | 830 | 3995 |
| Omastiná | city | Nitriansky | Slovakia | 48.78 | 18.39 | 1742 | 3272 |
| Omsenie | city | Nitriansky | Slovakia | 48.90 | 18.23 | 1669 | 13400 |
| Ondrejovce | city | Nitriansky | Slovakia | 48.14 | 18.52 | 830 | 4158 |
| Ondrochov | city | Nitriansky | Slovakia | 48.13 | 18.18 | 830 | 14201 |
| Ondrohó | city | Nitriansky | Slovakia | 48.13 | 18.18 | 830 | 14201 |
| Opatova | city | Nitriansky | Slovakia | 48.91 | 18.09 | 830 | 35669 |
| Opatovce | city | Nitriansky | Slovakia | 48.86 | 17.98 | 830 | 24050 |
| Opatovce nad Nitrou | city | Nitriansky | Slovakia | 48.76 | 18.57 | 830 | 29088 |
| Opatovce nad Zitavou | city | Nitriansky | Slovakia | 48.40 | 18.42 | 830 | 20350 |
| Opatová | city | Nitriansky | Slovakia | 48.28 | 18.65 | 830 | 4214 |
| Oponice | city | Nitriansky | Slovakia | 48.47 | 18.15 | 830 | 7348 |
| Ordódypuszta | city | Nitriansky | Slovakia | 47.92 | 18.22 | 830 | 11397 |
| Orešany | city | Nitriansky | Slovakia | 48.51 | 17.90 | 830 | 5396 |
| Orgonovci | city | Nitriansky | Slovakia | 49.25 | 18.34 | 1981 | 4240 |
| Orlove | city | Nitriansky | Slovakia | 49.13 | 18.43 | 925 | 35813 |
| Orlovský Dvor | city | Nitriansky | Slovakia | 49.12 | 18.43 | 1020 | 36975 |
| Oros | city | Nitriansky | Slovakia | 48.09 | 18.70 | 830 | 4691 |
| Oroska | city | Nitriansky | Slovakia | 47.97 | 18.66 | 406 | 5148 |
| Oroszka | city | Nitriansky | Slovakia | 47.97 | 18.66 | 406 | 5148 |
| Oroszlánkő | city | Nitriansky | Slovakia | 49.07 | 18.15 | 1669 | 3464 |
| Osikov Dvor | city | Nitriansky | Slovakia | 48.18 | 19.05 | 1669 | 2318 |
| Oslany | city | Nitriansky | Slovakia | 48.63 | 18.47 | 830 | 5980 |
| Oszlány | city | Nitriansky | Slovakia | 48.63 | 18.47 | 830 | 5980 |
| Osztopna | city | Nitriansky | Slovakia | 49.19 | 18.44 | 1246 | 12921 |
| Otrhánky | city | Nitriansky | Slovakia | 48.69 | 18.21 | 830 | 16058 |
| Otura,Ótura | city | Nitriansky | Slovakia | 48.78 | 17.69 | 859 | 11930 |
| Ovárky | city | Nitriansky | Slovakia | 48.15 | 18.64 | 830 | 16193 |