| Portalegre to Orbetello | 994.67 mi (1,600.76 km) |
| Portalegre to Oria | 1,325.69 mi (2,133.49 km) |
| Portalegre to Oristano | 851.93 mi (1,371.05 km) |
| Portalegre to Orta Nova | 1,222.57 mi (1,967.53 km) |
| Portalegre to Orte | 1,054.34 mi (1,696.80 km) |
| Portalegre to Ortona | 1,156.26 mi (1,860.83 km) |
| Portalegre to Orvieto | 1,042.19 mi (1,677.25 km) |
| Portalegre to Orzinuovi | 977.77 mi (1,573.57 km) |
| Portalegre to Osimo | 1,117.48 mi (1,798.40 km) |
| Portalegre to Ospitaletto | 987.75 mi (1,589.63 km) |
| Portalegre to Ostuni | 1,321.87 mi (2,127.34 km) |
| Portalegre to Ottaviano | 1,159.21 mi (1,865.57 km) |
| Portalegre to Ovada | 901.27 mi (1,450.46 km) |
| Portalegre to Ozieri | 872.83 mi (1,404.69 km) |
| Portalegre to Paceco | 1,079.13 mi (1,736.70 km) |
