| Oud-Heverlee to Oria | 946.82 mi (1,523.75 km) |
| Oud-Heverlee to Oristano | 778.39 mi (1,252.70 km) |
| Oud-Heverlee to Orta Nova | 841.47 mi (1,354.22 km) |
| Oud-Heverlee to Orte | 683.81 mi (1,100.49 km) |
| Oud-Heverlee to Ortona | 745.09 mi (1,199.11 km) |
| Oud-Heverlee to Orvieto | 661.39 mi (1,064.40 km) |
| Oud-Heverlee to Orzinuovi | 446.89 mi (719.21 km) |
| Oud-Heverlee to Osimo | 654.40 mi (1,053.15 km) |
| Oud-Heverlee to Ospitaletto | 441.32 mi (710.24 km) |
| Oud-Heverlee to Ostuni | 932.36 mi (1,500.49 km) |
| Oud-Heverlee to Ottaviano | 834.36 mi (1,342.77 km) |
| Oud-Heverlee to Ovada | 466.04 mi (750.02 km) |
| Oud-Heverlee to Ozieri | 738.03 mi (1,187.74 km) |
| Oud-Heverlee to Paceco | 968.04 mi (1,557.90 km) |
| Oud-Heverlee to Pachino | 1,103.06 mi (1,775.20 km) |
