| Gravelines to Oria | 1,037.16 mi (1,669.15 km) |
| Gravelines to Oristano | 826.45 mi (1,330.03 km) |
| Gravelines to Orta Nova | 928.66 mi (1,494.54 km) |
| Gravelines to Orte | 762.16 mi (1,226.57 km) |
| Gravelines to Ortona | 831.36 mi (1,337.95 km) |
| Gravelines to Orvieto | 739.49 mi (1,190.10 km) |
| Gravelines to Orzinuovi | 526.92 mi (848.00 km) |
| Gravelines to Osimo | 741.78 mi (1,193.78 km) |
| Gravelines to Ospitaletto | 523.21 mi (842.03 km) |
| Gravelines to Ostuni | 1,023.24 mi (1,646.75 km) |
| Gravelines to Ottaviano | 915.60 mi (1,473.52 km) |
| Gravelines to Ovada | 532.29 mi (856.63 km) |
| Gravelines to Ozieri | 790.52 mi (1,272.21 km) |
| Gravelines to Paceco | 1,032.64 mi (1,661.87 km) |
| Gravelines to Pachino | 1,175.09 mi (1,891.13 km) |
