| Rockford to Orbetello | 4,775.93 mi (7,686.12 km) |
| Rockford to Oria | 5,115.31 mi (8,232.30 km) |
| Rockford to Oristano | 4,778.37 mi (7,690.04 km) |
| Rockford to Orta Nova | 5,002.30 mi (8,050.43 km) |
| Rockford to Orte | 4,821.47 mi (7,759.40 km) |
| Rockford to Ortona | 4,905.18 mi (7,894.12 km) |
| Rockford to Orvieto | 4,799.32 mi (7,723.76 km) |
| Rockford to Orzinuovi | 4,599.83 mi (7,402.71 km) |
| Rockford to Osimo | 4,819.29 mi (7,755.90 km) |
| Rockford to Ospitaletto | 4,598.75 mi (7,400.97 km) |
| Rockford to Ostuni | 5,102.50 mi (8,211.68 km) |
| Rockford to Ottaviano | 4,975.71 mi (8,007.63 km) |
| Rockford to Ovada | 4,581.25 mi (7,372.80 km) |
| Rockford to Ozieri | 4,766.34 mi (7,670.68 km) |
| Rockford to Paceco | 5,026.98 mi (8,090.14 km) |
