| Boulogne-sur-Mer to Obernburg am Main | 337.75 mi (543.55 km) |
| Boulogne-sur-Mer to Obernkirchen | 339.65 mi (546.61 km) |
| Boulogne-sur-Mer to Oberschleissheim | 477.86 mi (769.04 km) |
| Boulogne-sur-Mer to Oberstdorf | 453.84 mi (730.38 km) |
| Boulogne-sur-Mer to Obertraubling | 485.16 mi (780.79 km) |
| Boulogne-sur-Mer to Obertshausen | 321.06 mi (516.70 km) |
| Boulogne-sur-Mer to Oberursel | 308.22 mi (496.03 km) |
| Boulogne-sur-Mer to Ochsenfurt | 381.00 mi (613.16 km) |
| Boulogne-sur-Mer to Ochsenhausen | 416.85 mi (670.86 km) |
| Boulogne-sur-Mer to Ochtrup | 260.76 mi (419.66 km) |
| Boulogne-sur-Mer to Odenthal | 240.73 mi (387.42 km) |
| Boulogne-sur-Mer to Oelde | 292.51 mi (470.74 km) |
| Boulogne-sur-Mer to Oelsnitz | 463.14 mi (745.36 km) |
| Boulogne-sur-Mer to Oer-Erkenschwick | 252.09 mi (405.70 km) |
| Boulogne-sur-Mer to Oerlinghausen | 316.03 mi (508.60 km) |
