| Romulus to Opwijk | 3,950.96 mi (6,358.45 km) |
| Romulus to Ostend | 3,894.11 mi (6,266.96 km) |
| Romulus to Oud-Heverlee | 3,973.87 mi (6,395.32 km) |
| Romulus to Oud-Turnhout | 3,969.93 mi (6,388.98 km) |
| Romulus to Oudenaarde | 3,932.36 mi (6,328.53 km) |
| Romulus to Oudenburg | 3,898.56 mi (6,274.12 km) |
| Romulus to Oupeye | 4,015.37 mi (6,462.12 km) |
| Romulus to Overijse | 3,970.41 mi (6,389.76 km) |
| Romulus to Overpelt | 3,989.68 mi (6,420.77 km) |
| Romulus to Paal | 3,986.34 mi (6,415.39 km) |
| Romulus to Peer | 3,993.88 mi (6,427.53 km) |
| Romulus to Pepinster | 4,026.80 mi (6,480.51 km) |
| Romulus to Peruwelz | 3,942.58 mi (6,344.97 km) |
| Romulus to Perwez | 3,986.51 mi (6,415.67 km) |
| Romulus to Philippeville | 3,990.46 mi (6,422.03 km) |
