| Portalegre to Opwijk | 981.08 mi (1,578.90 km) |
| Portalegre to Ostend | 962.09 mi (1,548.33 km) |
| Portalegre to Oud-Heverlee | 987.63 mi (1,589.44 km) |
| Portalegre to Oud-Turnhout | 1,021.90 mi (1,644.58 km) |
| Portalegre to Oudenaarde | 958.90 mi (1,543.20 km) |
| Portalegre to Oudenburg | 961.71 mi (1,547.73 km) |
| Portalegre to Oupeye | 1,010.04 mi (1,625.50 km) |
| Portalegre to Overijse | 981.21 mi (1,579.10 km) |
| Portalegre to Overpelt | 1,029.06 mi (1,656.12 km) |
| Portalegre to Paal | 1,012.87 mi (1,630.06 km) |
| Portalegre to Peer | 1,025.84 mi (1,650.92 km) |
| Portalegre to Pepinster | 1,008.34 mi (1,622.76 km) |
| Portalegre to Peruwelz | 940.41 mi (1,513.44 km) |
| Portalegre to Perwez | 981.09 mi (1,578.92 km) |
| Portalegre to Philippeville | 951.54 mi (1,531.35 km) |
