| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Oborki | city | Poland | 52.12 | 21.17 | 265 | 37288 | |
| Obory | city | Poland | 52.07 | 21.15 | 291 | 22863 | |
| Obręb | city | Poland | 51.97 | 21.13 | 410 | 10017 | |
| Ochota | city | Poland | 52.22 | 20.98 | 298 | 487849 | |
| Odolany | city | Poland | 52.22 | 20.92 | 314 | 313112 | |
| Odrana Wola | city | Poland | 52.08 | 20.65 | 337 | 28139 | |
| Odrona Wola | city | Poland | 52.08 | 20.65 | 337 | 28139 | |
| Odrzywol | city | Poland | 52.18 | 20.53 | 265 | 7652 | |
| Odrzywół | city | Poland | 52.18 | 20.53 | 265 | 7652 | |
| Okrzeszyn | city | Poland | 52.12 | 21.15 | 265 | 34129 | |
| Okuniew | city | Poland | 52.27 | 21.30 | 341 | 27965 | |
| Okunin | city | Poland | 52.43 | 20.75 | 203 | 20652 | |
| Okęcie | city | Poland | 52.18 | 20.95 | 291 | 245499 | |
| Olesin | city | Poland | 52.22 | 21.42 | 452 | 9561 | |
| Olesin | city | Poland | 52.35 | 21.07 | 249 | 43443 | |
| Olesin Dolny | city | Poland | 52.22 | 21.42 | 452 | 9561 | |
| Olesin Gorny | city | Poland | 52.23 | 21.42 | 462 | 9365 | |
| Olszewnica Nowa | city | Poland | 52.45 | 20.83 | 226 | 5621 | |
| Olszewnica Stara | city | Poland | 52.43 | 20.87 | 252 | 23692 | |
| Oltarzew | city | Poland | 52.22 | 20.78 | 318 | 46922 | |
| Opacz | city | Poland | 52.10 | 21.17 | 265 | 32537 | |
| Opacz | city | Poland | 52.17 | 20.92 | 308 | 139044 | |
| Opacz Duża | city | Poland | 52.17 | 20.92 | 308 | 139044 | |
| Opacz Mala | city | Poland | 52.17 | 20.90 | 311 | 130145 | |
| Opacz Mała | city | Poland | 52.17 | 20.90 | 311 | 130145 | |
| Opacz Wielka | city | Poland | 52.17 | 20.92 | 308 | 139044 | |
| Opypy | city | Poland | 52.10 | 20.68 | 341 | 34869 | |
| Orezna | city | Poland | 52.07 | 21.00 | 370 | 49438 | |
| Orzechowo | city | Poland | 52.50 | 20.87 | 285 | 5302 | |
| Orzeszyn | city | Poland | 52.02 | 21.10 | 370 | 18751 | |
| Osiedle Lacznosci Babice | city | Poland | 52.27 | 20.90 | 305 | 272890 | |
| Osiedle Łącznosci Babice | city | Poland | 52.27 | 20.90 | 305 | 272890 | |
| Ossow | city | Poland | 52.32 | 21.23 | 301 | 47794 | |
| Ostoja | city | Poland | 52.15 | 20.82 | 298 | 93152 | |
| Ostrow | city | Poland | 52.10 | 21.38 | 485 | 14883 | |
| Ostrzeszwo | city | Poland | 52.28 | 20.30 | 219 | 19305 | |
| Ostrzykowizna | city | Poland | 52.45 | 20.58 | 308 | 7328 | |
| Ostrówek | city | Poland | 52.00 | 21.25 | 305 | 9537 | |
| Otrebusy | city | Poland | 52.15 | 20.77 | 285 | 64221 | |
| Otrebusy | city | Poland | 52.08 | 20.78 | 337 | 10978 | |
| Otvotsk | city | Poland | 52.13 | 21.32 | 413 | 37105 | |
| Otwock | city | Poland | 52.13 | 21.32 | 413 | 37105 | |
| Otwock Maly | city | Poland | 52.05 | 21.25 | 282 | 26137 | |
| Otwock Mały | city | Poland | 52.05 | 21.25 | 282 | 26137 | |
| Otwock Wielki | city | Poland | 52.03 | 20.25 | 370 | 3789 | |
| Owczarnia | city | Poland | 52.10 | 20.72 | 328 | 25721 | |
| Ozarow-Franciszkow | city | Poland | 52.22 | 20.82 | 311 | 83389 | |
| Ołtarzew | city | Poland | 52.22 | 20.78 | 318 | 46922 | |
| Ożarów | city | Poland | 52.22 | 20.82 | 311 | 83389 | |
| Ożarów Mazowiecki | city | Poland | 52.23 | 20.85 | 321 | 130389 |