| Rio Maior to Octeville | 795.96 mi (1,280.97 km) |
| Rio Maior to Oignies | 963.24 mi (1,550.18 km) |
| Rio Maior to Oissel | 849.06 mi (1,366.44 km) |
| Rio Maior to Olivet | 799.27 mi (1,286.29 km) |
| Rio Maior to Ollioules | 810.41 mi (1,304.22 km) |
| Rio Maior to Olonne-sur-Mer | 614.96 mi (989.67 km) |
| Rio Maior to Oloron-Sainte-Marie | 507.74 mi (817.13 km) |
| Rio Maior to Onet Village | 686.70 mi (1,105.13 km) |
| Rio Maior to Onnaing | 977.06 mi (1,572.42 km) |
| Rio Maior to Orange | 781.17 mi (1,257.18 km) |
| Rio Maior to Orchies | 970.88 mi (1,562.48 km) |
| Rio Maior to Orleans | 801.39 mi (1,289.71 km) |
| Rio Maior to Orly | 857.92 mi (1,380.70 km) |
| Rio Maior to Ormesson-sur-Marne | 864.66 mi (1,391.54 km) |
| Rio Maior to Orsay | 849.09 mi (1,366.48 km) |
