| Castel San Pietro Terme to Opwijk | 568.90 mi (915.56 km) |
| Castel San Pietro Terme to Ostend | 618.85 mi (995.94 km) |
| Castel San Pietro Terme to Oud-Heverlee | 548.44 mi (882.62 km) |
| Castel San Pietro Terme to Oud-Turnhout | 566.94 mi (912.40 km) |
| Castel San Pietro Terme to Oudenaarde | 579.67 mi (932.89 km) |
| Castel San Pietro Terme to Oudenburg | 614.31 mi (988.64 km) |
| Castel San Pietro Terme to Oupeye | 516.05 mi (830.50 km) |
| Castel San Pietro Terme to Overijse | 549.41 mi (884.19 km) |
| Castel San Pietro Terme to Overpelt | 550.66 mi (886.19 km) |
| Castel San Pietro Terme to Paal | 546.54 mi (879.58 km) |
| Castel San Pietro Terme to Peer | 544.95 mi (877.01 km) |
| Castel San Pietro Terme to Pepinster | 503.68 mi (810.59 km) |
| Castel San Pietro Terme to Peruwelz | 563.52 mi (906.89 km) |
| Castel San Pietro Terme to Perwez | 533.10 mi (857.94 km) |
| Castel San Pietro Terme to Philippeville | 518.37 mi (834.23 km) |
