| Gretna to Opwijk | 4,815.43 mi (7,749.69 km) |
| Gretna to Ostend | 4,757.90 mi (7,657.11 km) |
| Gretna to Oud-Heverlee | 4,838.42 mi (7,786.69 km) |
| Gretna to Oud-Turnhout | 4,837.88 mi (7,785.82 km) |
| Gretna to Oudenaarde | 4,795.08 mi (7,716.94 km) |
| Gretna to Oudenburg | 4,762.24 mi (7,664.08 km) |
| Gretna to Oupeye | 4,880.99 mi (7,855.19 km) |
| Gretna to Overijse | 4,834.43 mi (7,780.26 km) |
| Gretna to Overpelt | 4,857.82 mi (7,817.91 km) |
| Gretna to Paal | 4,853.02 mi (7,810.19 km) |
| Gretna to Peer | 4,861.61 mi (7,824.00 km) |
| Gretna to Pepinster | 4,891.91 mi (7,872.78 km) |
| Gretna to Peruwelz | 4,803.23 mi (7,730.04 km) |
| Gretna to Perwez | 4,850.10 mi (7,805.48 km) |
| Gretna to Philippeville | 4,851.00 mi (7,806.92 km) |
