| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Onans | city | Franche-Comte | France | 47.50 | 6.61 | 1669 | 4647 |
| Onard | city | Aquitaine | France | 43.78 | -0.84 | 49 | 4603 |
| Onay | city | Franche-Comte | France | 47.39 | 5.69 | 830 | 1722 |
| Oncieu | city | Rhone-Alpes | France | 45.96 | 5.47 | 2559 | 3318 |
| Oncourt | city | Lorraine | France | 48.25 | 6.38 | 1207 | 14751 |
| Oncques | city | Centre-Val de Loire | France | 47.82 | 1.29 | 410 | 1956 |
| Oncy | city | France | 48.38 | 2.47 | 213 | 7392 | |
| Ondas | city | Midi-Pyrenees | France | 43.78 | 1.31 | 357 | 14054 |
| Ondefontaine | city | Basse-Normandie | France | 49.00 | -0.69 | 961 | 3385 |
| Ondes | city | Midi-Pyrenees | France | 43.78 | 1.31 | 357 | 14054 |
| Ondres | city | Provence-Alpes-Cote d'Azur | France | 44.12 | 6.59 | 5029 | 391 |
| Ondres | city | Aquitaine | France | 43.56 | -1.44 | 121 | 28775 |
| Ondreville | city | Centre-Val de Loire | France | 48.20 | 2.41 | 341 | 4224 |
| Ondreville | city | Centre-Val de Loire | France | 48.17 | 1.95 | 830 | 4135 |
| Ondreville-sur-Essonne | city | Centre-Val de Loire | France | 48.20 | 2.41 | 341 | 4224 |
| Onesse | city | Aquitaine | France | 44.06 | -1.07 | 177 | 682 |
| Onesse-Laharie | city | Aquitaine | France | 44.06 | -1.07 | 177 | 682 |
| Onesse-et-Laharie | city | Aquitaine | France | 44.06 | -1.07 | 177 | 682 |
| Onet | city | Midi-Pyrenees | France | 44.39 | 2.54 | 1942 | 31606 |
| Onet-le-Château | city | Midi-Pyrenees | France | 44.39 | 2.54 | 1942 | 31606 |
| Oneux | city | Picardie | France | 50.14 | 1.97 | 177 | 2548 |
| Onglas | city | Rhone-Alpes | France | 45.82 | 5.48 | 1860 | 3686 |
| Ongles | city | Provence-Alpes-Cote d'Azur | France | 44.03 | 5.73 | 1922 | 1381 |
| Onglevert | city | Nord-Pas-de-Calais | France | 50.84 | 1.62 | 370 | 9156 |
| Onglieres | city | Franche-Comte | France | 46.79 | 6.01 | 2568 | 1536 |
| Onicourt | city | Picardie | France | 50.02 | 1.73 | 347 | 3694 |
| Onival | city | Picardie | France | 50.11 | 1.46 | 242 | 7965 |
| Onjon | city | Champagne-Ardenne | France | 48.39 | 4.28 | 830 | 1061 |
| Onlay | city | Bourgogne | France | 46.97 | 3.90 | 1184 | 1045 |
| Onnaing | city | Nord-Pas-de-Calais | France | 50.39 | 3.60 | 124 | 51588 |
| Onnex | city | Rhone-Alpes | France | 45.94 | 6.17 | 1906 | 49868 |
| Onnion | city | Rhone-Alpes | France | 46.17 | 6.48 | 2700 | 5626 |
| Onnod-Raez | city | Pays de la Loire | France | 47.02 | -1.88 | 39 | 5130 |
| Onoz | city | Franche-Comte | France | 46.46 | 5.65 | 1870 | 1991 |
| Ons | city | Picardie | France | 49.42 | 1.92 | 377 | 6718 |
| Ons-en-Bray | city | Picardie | France | 49.42 | 1.92 | 377 | 6718 |
| Onsac | city | Auvergne | France | 44.96 | 2.59 | 2509 | 3666 |
| Onsembray | city | Picardie | France | 49.42 | 1.92 | 377 | 6718 |
| Ontex | city | Rhone-Alpes | France | 45.75 | 5.82 | 1988 | 3469 |
| Onville | city | Lorraine | France | 49.02 | 5.97 | 830 | 5731 |
| Onville | city | Centre-Val de Loire | France | 48.20 | 2.11 | 403 | 2081 |
| Onville-sur-Mad | city | Lorraine | France | 49.02 | 5.97 | 830 | 5731 |
| Onvillers | city | Picardie | France | 49.61 | 2.67 | 334 | 2601 |
| Onzain | city | Centre-Val de Loire | France | 47.50 | 1.18 | 203 | 5097 |
| Onzay | city | Centre-Val de Loire | France | 46.93 | 1.32 | 344 | 2133 |
| Onzay-Palluau | city | Centre-Val de Loire | France | 46.93 | 1.32 | 344 | 2133 |
| Onzillon | city | Auvergne | France | 44.94 | 3.93 | 2811 | 3605 |