| Rockford to Octeville | 3,988.78 mi (6,419.32 km) |
| Rockford to Oignies | 4,137.52 mi (6,658.69 km) |
| Rockford to Oissel | 4,105.02 mi (6,606.39 km) |
| Rockford to Olivet | 4,189.67 mi (6,742.62 km) |
| Rockford to Ollioules | 4,530.36 mi (7,290.91 km) |
| Rockford to Olonne-sur-Mer | 4,089.78 mi (6,581.87 km) |
| Rockford to Oloron-Sainte-Marie | 4,259.73 mi (6,855.37 km) |
| Rockford to Onet Village | 4,348.73 mi (6,998.61 km) |
| Rockford to Onnaing | 4,163.15 mi (6,699.95 km) |
| Rockford to Orange | 4,448.08 mi (7,158.49 km) |
| Rockford to Orchies | 4,146.73 mi (6,673.52 km) |
| Rockford to Orleans | 4,188.59 mi (6,740.88 km) |
| Rockford to Orly | 4,176.84 mi (6,721.97 km) |
| Rockford to Ormesson-sur-Marne | 4,180.95 mi (6,728.58 km) |
| Rockford to Orsay | 4,170.54 mi (6,711.83 km) |
