| Castelo Branco to Nuth | 1,001.94 mi (1,612.47 km) |
| Castelo Branco to Oegstgeest | 1,026.61 mi (1,652.17 km) |
| Castelo Branco to Oirschot | 1,013.61 mi (1,631.25 km) |
| Castelo Branco to Oisterwijk | 1,015.02 mi (1,633.51 km) |
| Castelo Branco to Oldebroek | 1,079.57 mi (1,737.41 km) |
| Castelo Branco to Oldenzaal | 1,102.40 mi (1,774.14 km) |
| Castelo Branco to Ommen | 1,097.53 mi (1,766.30 km) |
| Castelo Branco to Oosterend | 1,113.04 mi (1,791.26 km) |
| Castelo Branco to Oosterhout | 1,008.42 mi (1,622.90 km) |
| Castelo Branco to Oosterwolde | 1,118.45 mi (1,799.97 km) |
| Castelo Branco to Oostzaan | 1,051.09 mi (1,691.57 km) |
| Castelo Branco to Opmeer | 1,067.23 mi (1,717.54 km) |
| Castelo Branco to Oss | 1,033.51 mi (1,663.28 km) |
| Castelo Branco to Oud-Beijerland | 1,005.08 mi (1,617.52 km) |
| Castelo Branco to Oudenbosch | 996.33 mi (1,603.45 km) |
