| Castaic to Octeville | 5,465.67 mi (8,796.15 km) |
| Castaic to Oignies | 5,576.07 mi (8,973.82 km) |
| Castaic to Oissel | 5,569.43 mi (8,963.13 km) |
| Castaic to Olivet | 5,666.83 mi (9,119.88 km) |
| Castaic to Ollioules | 6,033.80 mi (9,710.46 km) |
| Castaic to Olonne-sur-Mer | 5,603.40 mi (9,017.79 km) |
| Castaic to Oloron-Sainte-Marie | 5,801.36 mi (9,336.39 km) |
| Castaic to Onet Village | 5,860.13 mi (9,430.96 km) |
| Castaic to Onnaing | 5,598.89 mi (9,010.55 km) |
| Castaic to Orange | 5,947.99 mi (9,572.36 km) |
| Castaic to Orchies | 5,583.63 mi (8,985.98 km) |
| Castaic to Orleans | 5,665.25 mi (9,117.34 km) |
| Castaic to Orly | 5,640.53 mi (9,077.56 km) |
| Castaic to Ormesson-sur-Marne | 5,643.23 mi (9,081.91 km) |
| Castaic to Orsay | 5,636.06 mi (9,070.36 km) |
