| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Oaki | city | Gifu | Japan | 35.35 | 136.62 | 68 | 159513 |
| Obota | city | Gifu | Japan | 35.18 | 136.63 | 3 | 32088 |
| Ochiai | city | Gifu | Japan | 35.52 | 137.53 | 1669 | 30997 |
| Ogimachi | city | Gifu | Japan | 36.26 | 136.91 | 2509 | 597 |
| Oi | city | Gifu | Japan | 35.45 | 137.42 | 958 | 38988 |
| Oicho | city | Gifu | Japan | 35.45 | 137.42 | 958 | 38988 |
| Oimachi | city | Gifu | Japan | 35.45 | 137.42 | 958 | 38988 |
| Oku-shinden | city | Gifu | Japan | 35.58 | 137.37 | 1968 | 4769 |
| Okuasoya | city | Gifu | Japan | 36.32 | 137.34 | 2509 | 6814 |
| Okuhida-onsengo-hirayu | city | Gifu | Japan | 36.19 | 137.55 | 4265 | 711 |
| Okuhida-onsengo-hitoegane | city | Gifu | Japan | 36.24 | 137.53 | 3349 | 818 |
| Okuhida-onsengo-nakao | city | Gifu | Japan | 36.26 | 137.57 | 3608 | 871 |
| Okuhida-onsengō-imami | city | Gifu | Japan | 36.25 | 137.50 | 2601 | 788 |
| Okuhida-onsengō-tochio | city | Gifu | Japan | 36.25 | 137.52 | 2854 | 836 |
| Onishi | city | Gifu | Japan | 36.09 | 137.30 | 2509 | 22624 |
| Onota | city | Gifu | Japan | 35.60 | 137.03 | 984 | 8797 |
| Oroshi | city | Gifu | Japan | 35.32 | 137.18 | 830 | 87327 |
| Oroshi | city | Gifu | Japan | 35.32 | 137.20 | 830 | 64280 |
| Osaka | city | Gifu | Japan | 35.95 | 137.27 | 1899 | 2598 |
| Ota | city | Gifu | Japan | 35.18 | 136.63 | 3 | 32088 |
| Otohara | city | Gifu | Japan | 35.53 | 136.53 | 830 | 9111 |
| Otowara | city | Gifu | Japan | 35.53 | 136.53 | 830 | 9111 |
| Owashi | city | Gifu | Japan | 35.95 | 136.87 | 1833 | 4362 |