| Castel San Pietro Terme to Octeville | 718.71 mi (1,156.65 km) |
| Castel San Pietro Terme to Oignies | 579.80 mi (933.09 km) |
| Castel San Pietro Terme to Oissel | 600.96 mi (967.16 km) |
| Castel San Pietro Terme to Olivet | 521.23 mi (838.84 km) |
| Castel San Pietro Terme to Ollioules | 299.10 mi (481.35 km) |
| Castel San Pietro Terme to Olonne-sur-Mer | 662.92 mi (1,066.86 km) |
| Castel San Pietro Terme to Oloron-Sainte-Marie | 613.03 mi (986.57 km) |
| Castel San Pietro Terme to Onet Village | 443.69 mi (714.05 km) |
| Castel San Pietro Terme to Onnaing | 556.74 mi (895.98 km) |
| Castel San Pietro Terme to Orange | 335.52 mi (539.97 km) |
| Castel San Pietro Terme to Orchies | 572.06 mi (920.65 km) |
| Castel San Pietro Terme to Orleans | 521.96 mi (840.01 km) |
| Castel San Pietro Terme to Orly | 529.17 mi (851.62 km) |
| Castel San Pietro Terme to Ormesson-sur-Marne | 525.03 mi (844.96 km) |
| Castel San Pietro Terme to Orsay | 535.61 mi (861.99 km) |
