| Santo Tirso to Oerlinghausen | 1,090.52 mi (1,755.03 km) |
| Santo Tirso to Oestrich-Winkel | 991.72 mi (1,596.02 km) |
| Santo Tirso to Offenburg | 938.96 mi (1,511.11 km) |
| Santo Tirso to Oftersheim | 993.33 mi (1,598.62 km) |
| Santo Tirso to Ohrdruf | 1,124.60 mi (1,809.87 km) |
| Santo Tirso to Ohringen | 1,025.06 mi (1,649.67 km) |
| Santo Tirso to Olbernhau | 1,222.12 mi (1,966.81 km) |
| Santo Tirso to Olching | 1,076.01 mi (1,731.67 km) |
| Santo Tirso to Oldenburg | 1,125.21 mi (1,810.84 km) |
| Santo Tirso to Oldenburg in Holstein | 1,260.32 mi (2,028.28 km) |
| Santo Tirso to Olfen | 1,036.24 mi (1,667.66 km) |
| Santo Tirso to Olpe | 1,023.48 mi (1,647.13 km) |
| Santo Tirso to Olsberg | 1,059.71 mi (1,705.45 km) |
| Santo Tirso to Oranienburg | 1,282.49 mi (2,063.96 km) |
| Santo Tirso to Ortenberg | 1,044.44 mi (1,680.86 km) |
