| Boulogne-sur-Mer to Oestrich-Winkel | 285.78 mi (459.92 km) |
| Boulogne-sur-Mer to Offenburg | 323.03 mi (519.87 km) |
| Boulogne-sur-Mer to Oftersheim | 322.97 mi (519.78 km) |
| Boulogne-sur-Mer to Ohrdruf | 398.18 mi (640.81 km) |
| Boulogne-sur-Mer to Ohringen | 365.79 mi (588.68 km) |
| Boulogne-sur-Mer to Olbernhau | 512.35 mi (824.55 km) |
| Boulogne-sur-Mer to Olching | 468.90 mi (754.62 km) |
| Boulogne-sur-Mer to Oldenburg | 326.81 mi (525.96 km) |
| Boulogne-sur-Mer to Oldenburg in Holstein | 460.81 mi (741.61 km) |
| Boulogne-sur-Mer to Olfen | 258.76 mi (416.43 km) |
| Boulogne-sur-Mer to Olpe | 271.80 mi (437.43 km) |
| Boulogne-sur-Mer to Olsberg | 301.39 mi (485.04 km) |
| Boulogne-sur-Mer to Oranienburg | 515.96 mi (830.36 km) |
| Boulogne-sur-Mer to Ortenberg | 327.58 mi (527.19 km) |
| Boulogne-sur-Mer to Oschatz | 500.63 mi (805.68 km) |
