| Arouca to Orbetello | 1,007.11 mi (1,620.79 km) |
| Arouca to Oria | 1,350.58 mi (2,173.54 km) |
| Arouca to Oristano | 887.09 mi (1,427.64 km) |
| Arouca to Orta Nova | 1,243.03 mi (2,000.46 km) |
| Arouca to Orte | 1,066.91 mi (1,717.03 km) |
| Arouca to Ortona | 1,169.87 mi (1,882.72 km) |
| Arouca to Orvieto | 1,052.65 mi (1,694.08 km) |
| Arouca to Orzinuovi | 964.14 mi (1,551.63 km) |
| Arouca to Osimo | 1,122.56 mi (1,806.58 km) |
| Arouca to Ospitaletto | 973.07 mi (1,566.01 km) |
| Arouca to Ostuni | 1,345.35 mi (2,165.13 km) |
| Arouca to Ottaviano | 1,183.46 mi (1,904.60 km) |
| Arouca to Ovada | 892.06 mi (1,435.63 km) |
| Arouca to Ozieri | 901.55 mi (1,450.90 km) |
| Arouca to Paceco | 1,125.10 mi (1,810.67 km) |
