| Viana do Castelo to Oerlinghausen | 1,084.68 mi (1,745.62 km) |
| Viana do Castelo to Oestrich-Winkel | 988.90 mi (1,591.49 km) |
| Viana do Castelo to Offenburg | 939.21 mi (1,511.52 km) |
| Viana do Castelo to Oftersheim | 992.15 mi (1,596.71 km) |
| Viana do Castelo to Ohrdruf | 1,122.01 mi (1,805.70 km) |
| Viana do Castelo to Ohringen | 1,024.77 mi (1,649.21 km) |
| Viana do Castelo to Olbernhau | 1,221.12 mi (1,965.20 km) |
| Viana do Castelo to Olching | 1,078.60 mi (1,735.83 km) |
| Viana do Castelo to Oldenburg | 1,117.19 mi (1,797.95 km) |
| Viana do Castelo to Oldenburg in Holstein | 1,252.40 mi (2,015.55 km) |
| Viana do Castelo to Olfen | 1,029.86 mi (1,657.39 km) |
| Viana do Castelo to Olpe | 1,018.66 mi (1,639.37 km) |
| Viana do Castelo to Olsberg | 1,054.78 mi (1,697.50 km) |
| Viana do Castelo to Oranienburg | 1,278.11 mi (2,056.92 km) |
| Viana do Castelo to Ortenberg | 1,041.67 mi (1,676.40 km) |
