| Grevena to Octeville | 1,300.44 mi (2,092.86 km) |
| Grevena to Oignies | 1,142.62 mi (1,838.88 km) |
| Grevena to Oissel | 1,179.97 mi (1,898.98 km) |
| Grevena to Olivet | 1,105.30 mi (1,778.80 km) |
| Grevena to Ollioules | 830.70 mi (1,336.88 km) |
| Grevena to Olonne-sur-Mer | 1,243.02 mi (2,000.45 km) |
| Grevena to Oloron-Sainte-Marie | 1,154.34 mi (1,857.72 km) |
| Grevena to Onet Village | 1,005.36 mi (1,617.97 km) |
| Grevena to Onnaing | 1,117.12 mi (1,797.83 km) |
| Grevena to Orange | 894.76 mi (1,439.98 km) |
| Grevena to Orchies | 1,133.48 mi (1,824.17 km) |
| Grevena to Orleans | 1,105.93 mi (1,779.82 km) |
| Grevena to Orly | 1,109.02 mi (1,784.80 km) |
| Grevena to Ormesson-sur-Marne | 1,104.31 mi (1,777.21 km) |
| Grevena to Orsay | 1,116.13 mi (1,796.24 km) |
