| West Chicago to Octeville | 3,971.98 mi (6,392.28 km) |
| West Chicago to Oignies | 4,122.85 mi (6,635.08 km) |
| West Chicago to Oissel | 4,088.82 mi (6,580.32 km) |
| West Chicago to Olivet | 4,172.53 mi (6,715.03 km) |
| West Chicago to Ollioules | 4,511.03 mi (7,259.81 km) |
| West Chicago to Olonne-sur-Mer | 4,070.38 mi (6,550.64 km) |
| West Chicago to Oloron-Sainte-Marie | 4,238.11 mi (6,820.58 km) |
| West Chicago to Onet Village | 4,329.12 mi (6,967.04 km) |
| West Chicago to Onnaing | 4,148.61 mi (6,676.53 km) |
| West Chicago to Orange | 4,429.09 mi (7,127.93 km) |
| West Chicago to Orchies | 4,132.15 mi (6,650.05 km) |
| West Chicago to Orleans | 4,171.48 mi (6,713.35 km) |
| West Chicago to Orly | 4,160.57 mi (6,695.78 km) |
| West Chicago to Ormesson-sur-Marne | 4,164.76 mi (6,702.53 km) |
| West Chicago to Orsay | 4,154.16 mi (6,685.48 km) |
