| Mercer Island to Opwijk | 4,924.51 mi (7,925.24 km) |
| Mercer Island to Ostend | 4,878.16 mi (7,850.63 km) |
| Mercer Island to Oud-Heverlee | 4,944.11 mi (7,956.77 km) |
| Mercer Island to Oud-Turnhout | 4,924.43 mi (7,925.10 km) |
| Mercer Island to Oudenaarde | 4,916.47 mi (7,912.30 km) |
| Mercer Island to Oudenburg | 4,882.58 mi (7,857.75 km) |
| Mercer Island to Oupeye | 4,975.32 mi (8,007.00 km) |
| Mercer Island to Overijse | 4,943.63 mi (7,956.01 km) |
| Mercer Island to Overpelt | 4,940.72 mi (7,951.32 km) |
| Mercer Island to Paal | 4,944.88 mi (7,958.01 km) |
| Mercer Island to Peer | 4,946.41 mi (7,960.48 km) |
| Mercer Island to Pepinster | 4,987.68 mi (8,026.90 km) |
| Mercer Island to Peruwelz | 4,934.85 mi (7,941.88 km) |
| Mercer Island to Perwez | 4,959.69 mi (7,981.85 km) |
| Mercer Island to Philippeville | 4,977.19 mi (8,010.02 km) |
