| Castleford to Orbetello | 968.40 mi (1,558.49 km) |
| Castleford to Oria | 1,269.44 mi (2,042.96 km) |
| Castleford to Oristano | 1,061.48 mi (1,708.28 km) |
| Castleford to Orta Nova | 1,162.99 mi (1,871.65 km) |
| Castleford to Orte | 999.94 mi (1,609.25 km) |
| Castleford to Ortona | 1,066.12 mi (1,715.76 km) |
| Castleford to Orvieto | 977.31 mi (1,572.83 km) |
| Castleford to Orzinuovi | 763.79 mi (1,229.19 km) |
| Castleford to Osimo | 975.82 mi (1,570.42 km) |
| Castleford to Ospitaletto | 759.42 mi (1,222.16 km) |
| Castleford to Ostuni | 1,255.10 mi (2,019.89 km) |
| Castleford to Ottaviano | 1,152.66 mi (1,855.03 km) |
| Castleford to Ovada | 771.35 mi (1,241.36 km) |
| Castleford to Ozieri | 1,027.17 mi (1,653.06 km) |
| Castleford to Paceco | 1,271.44 mi (2,046.18 km) |
