| Montemor-o-Velho to Nuth | 1,020.39 mi (1,642.17 km) |
| Montemor-o-Velho to Oegstgeest | 1,038.31 mi (1,670.99 km) |
| Montemor-o-Velho to Oirschot | 1,029.07 mi (1,656.12 km) |
| Montemor-o-Velho to Oisterwijk | 1,030.01 mi (1,657.64 km) |
| Montemor-o-Velho to Oldebroek | 1,093.34 mi (1,759.57 km) |
| Montemor-o-Velho to Oldenzaal | 1,118.43 mi (1,799.95 km) |
| Montemor-o-Velho to Ommen | 1,112.06 mi (1,789.68 km) |
| Montemor-o-Velho to Oosterend | 1,125.55 mi (1,811.39 km) |
| Montemor-o-Velho to Oosterhout | 1,022.53 mi (1,645.61 km) |
| Montemor-o-Velho to Oosterwolde | 1,131.41 mi (1,820.83 km) |
| Montemor-o-Velho to Oostzaan | 1,062.93 mi (1,710.61 km) |
| Montemor-o-Velho to Opmeer | 1,078.45 mi (1,735.59 km) |
| Montemor-o-Velho to Oss | 1,048.57 mi (1,687.51 km) |
| Montemor-o-Velho to Oud-Beijerland | 1,017.71 mi (1,637.85 km) |
| Montemor-o-Velho to Oudenbosch | 1,009.91 mi (1,625.30 km) |
