| Prospect Heights to Octeville | 3,951.00 mi (6,358.52 km) |
| Prospect Heights to Oignies | 4,101.84 mi (6,601.27 km) |
| Prospect Heights to Oissel | 4,067.83 mi (6,546.54 km) |
| Prospect Heights to Olivet | 4,151.56 mi (6,681.29 km) |
| Prospect Heights to Ollioules | 4,490.16 mi (7,226.21 km) |
| Prospect Heights to Olonne-sur-Mer | 4,049.51 mi (6,517.05 km) |
| Prospect Heights to Oloron-Sainte-Marie | 4,217.38 mi (6,787.22 km) |
| Prospect Heights to Onet Village | 4,308.26 mi (6,933.47 km) |
| Prospect Heights to Onnaing | 4,127.60 mi (6,642.72 km) |
| Prospect Heights to Orange | 4,408.20 mi (7,094.31 km) |
| Prospect Heights to Orchies | 4,111.14 mi (6,616.24 km) |
| Prospect Heights to Orleans | 4,150.52 mi (6,679.61 km) |
| Prospect Heights to Orly | 4,139.58 mi (6,662.01 km) |
| Prospect Heights to Ormesson-sur-Marne | 4,143.77 mi (6,668.75 km) |
| Prospect Heights to Orsay | 4,133.18 mi (6,651.71 km) |
