| Cascais to Octeville | 846.52 mi (1,362.35 km) |
| Cascais to Oignies | 1,014.07 mi (1,631.99 km) |
| Cascais to Oissel | 899.92 mi (1,448.29 km) |
| Cascais to Olivet | 849.66 mi (1,367.39 km) |
| Cascais to Ollioules | 852.34 mi (1,371.70 km) |
| Cascais to Olonne-sur-Mer | 665.77 mi (1,071.45 km) |
| Cascais to Oloron-Sainte-Marie | 554.33 mi (892.10 km) |
| Cascais to Onet Village | 733.10 mi (1,179.81 km) |
| Cascais to Onnaing | 1,027.83 mi (1,654.13 km) |
| Cascais to Orange | 825.79 mi (1,328.98 km) |
| Cascais to Orchies | 1,021.70 mi (1,644.26 km) |
| Cascais to Orleans | 851.79 mi (1,370.82 km) |
| Cascais to Orly | 908.52 mi (1,462.11 km) |
| Cascais to Ormesson-sur-Marne | 915.24 mi (1,472.93 km) |
| Cascais to Orsay | 899.71 mi (1,447.94 km) |
