| Castaic to Oerlinghausen | 5,669.65 mi (9,124.42 km) |
| Castaic to Oestrich-Winkel | 5,751.99 mi (9,256.93 km) |
| Castaic to Offenburg | 5,829.04 mi (9,380.93 km) |
| Castaic to Oftersheim | 5,801.87 mi (9,337.21 km) |
| Castaic to Ohrdruf | 5,787.35 mi (9,313.84 km) |
| Castaic to Ohringen | 5,837.82 mi (9,395.06 km) |
| Castaic to Olbernhau | 5,867.45 mi (9,442.75 km) |
| Castaic to Olching | 5,943.99 mi (9,565.92 km) |
| Castaic to Oldenburg | 5,596.25 mi (9,006.30 km) |
| Castaic to Oldenburg in Holstein | 5,607.53 mi (9,024.45 km) |
| Castaic to Olfen | 5,645.91 mi (9,086.21 km) |
| Castaic to Olpe | 5,694.79 mi (9,164.87 km) |
| Castaic to Olsberg | 5,696.35 mi (9,167.39 km) |
| Castaic to Oranienburg | 5,751.36 mi (9,255.92 km) |
| Castaic to Ortenberg | 5,764.43 mi (9,276.96 km) |
