| Boulogne-sur-Mer to Oignies | 63.03 mi (101.44 km) |
| Boulogne-sur-Mer to Oissel | 98.44 mi (158.42 km) |
| Boulogne-sur-Mer to Olivet | 198.20 mi (318.97 km) |
| Boulogne-sur-Mer to Ollioules | 560.71 mi (902.38 km) |
| Boulogne-sur-Mer to Olonne-sur-Mer | 328.17 mi (528.14 km) |
| Boulogne-sur-Mer to Oloron-Sainte-Marie | 530.80 mi (854.23 km) |
| Boulogne-sur-Mer to Onet Village | 441.84 mi (711.08 km) |
| Boulogne-sur-Mer to Onnaing | 90.15 mi (145.08 km) |
| Boulogne-sur-Mer to Orange | 478.94 mi (770.78 km) |
| Boulogne-sur-Mer to Orchies | 73.55 mi (118.36 km) |
| Boulogne-sur-Mer to Orleans | 195.56 mi (314.73 km) |
| Boulogne-sur-Mer to Orly | 141.31 mi (227.42 km) |
| Boulogne-sur-Mer to Ormesson-sur-Marne | 140.27 mi (225.75 km) |
| Boulogne-sur-Mer to Orsay | 142.46 mi (229.26 km) |
| Boulogne-sur-Mer to Orthez | 512.47 mi (824.74 km) |
