| Castleford to Olympia Heights (Florida) | 4,362.79 mi (7,021.23 km) |
| Castleford to Omaha (Nebraska) | 4,167.49 mi (6,706.93 km) |
| Castleford to On Top of the World Designated Place (Florida) | 4,265.22 mi (6,864.21 km) |
| Castleford to Onalaska (Wisconsin) | 3,865.69 mi (6,221.22 km) |
| Castleford to Oneida (New York) | 3,325.31 mi (5,351.57 km) |
| Castleford to Oneonta (New York) | 3,329.98 mi (5,359.09 km) |
| Castleford to Ontario (California) | 5,282.06 mi (8,500.65 km) |
| Castleford to Ontario (Oregon) | 4,691.41 mi (7,550.09 km) |
| Castleford to Opa-locka (Florida) | 4,350.19 mi (7,000.95 km) |
| Castleford to Opelika (Alabama) | 4,205.13 mi (6,767.50 km) |
| Castleford to Opelousas (Louisiana) | 4,576.45 mi (7,365.09 km) |
| Castleford to Orange (California) | 5,302.43 mi (8,533.44 km) |
| Castleford to Orange (Texas) | 4,662.17 mi (7,503.04 km) |
| Castleford to Orange City (Florida) | 4,234.00 mi (6,813.96 km) |
| Castleford to Orangeburg (South Carolina) | 3,985.19 mi (6,413.54 km) |
