| Boulogne-sur-Mer to Oria | 1,044.05 mi (1,680.23 km) |
| Boulogne-sur-Mer to Oristano | 820.00 mi (1,319.66 km) |
| Boulogne-sur-Mer to Orta Nova | 934.45 mi (1,503.85 km) |
| Boulogne-sur-Mer to Orte | 765.08 mi (1,231.28 km) |
| Boulogne-sur-Mer to Ortona | 836.98 mi (1,346.98 km) |
| Boulogne-sur-Mer to Orvieto | 742.40 mi (1,194.78 km) |
| Boulogne-sur-Mer to Orzinuovi | 531.36 mi (855.14 km) |
| Boulogne-sur-Mer to Osimo | 748.03 mi (1,203.83 km) |
| Boulogne-sur-Mer to Ospitaletto | 528.31 mi (850.23 km) |
| Boulogne-sur-Mer to Ostuni | 1,030.37 mi (1,658.21 km) |
| Boulogne-sur-Mer to Ottaviano | 919.19 mi (1,479.30 km) |
| Boulogne-sur-Mer to Ovada | 532.30 mi (856.65 km) |
| Boulogne-sur-Mer to Ozieri | 785.40 mi (1,263.98 km) |
| Boulogne-sur-Mer to Paceco | 1,030.52 mi (1,658.46 km) |
| Boulogne-sur-Mer to Pachino | 1,175.13 mi (1,891.19 km) |
