| Castelo Branco to Opwijk | 954.02 mi (1,535.34 km) |
| Castelo Branco to Ostend | 933.81 mi (1,502.82 km) |
| Castelo Branco to Oud-Heverlee | 961.07 mi (1,546.70 km) |
| Castelo Branco to Oud-Turnhout | 995.07 mi (1,601.41 km) |
| Castelo Branco to Oudenaarde | 931.50 mi (1,499.10 km) |
| Castelo Branco to Oudenburg | 933.54 mi (1,502.38 km) |
| Castelo Branco to Oupeye | 984.35 mi (1,584.16 km) |
| Castelo Branco to Overijse | 954.60 mi (1,536.28 km) |
| Castelo Branco to Overpelt | 1,002.65 mi (1,613.61 km) |
| Castelo Branco to Paal | 986.47 mi (1,587.57 km) |
| Castelo Branco to Peer | 999.54 mi (1,608.60 km) |
| Castelo Branco to Pepinster | 982.95 mi (1,581.90 km) |
| Castelo Branco to Peruwelz | 913.34 mi (1,469.87 km) |
| Castelo Branco to Perwez | 954.88 mi (1,536.73 km) |
| Castelo Branco to Philippeville | 925.60 mi (1,489.61 km) |
