| Rockford to Olivares | 4,231.36 mi (6,809.71 km) |
| Rockford to Olivenza | 4,140.52 mi (6,663.53 km) |
| Rockford to Olot | 4,429.29 mi (7,128.26 km) |
| Rockford to Onate | 4,188.61 mi (6,740.92 km) |
| Rockford to Onda | 4,397.98 mi (7,077.86 km) |
| Rockford to Onteniente | 4,427.49 mi (7,125.36 km) |
| Rockford to Orihuela | 4,441.39 mi (7,147.72 km) |
| Rockford to Osuna | 4,286.52 mi (6,898.49 km) |
| Rockford to Ourense | 3,976.14 mi (6,398.99 km) |
| Rockford to Oviedo | 4,029.15 mi (6,484.29 km) |
| Rockford to Paiporta | 4,412.09 mi (7,100.57 km) |
| Rockford to Pajara | 4,198.83 mi (6,757.36 km) |
| Rockford to Palafolls | 4,460.58 mi (7,178.61 km) |
| Rockford to Palafrugell | 4,468.13 mi (7,190.76 km) |
| Rockford to Palamos | 4,469.53 mi (7,193.02 km) |
