| Naperville to Orbetello | 4,762.20 mi (7,664.02 km) |
| Naperville to Oria | 5,103.27 mi (8,212.93 km) |
| Naperville to Oristano | 4,761.27 mi (7,662.53 km) |
| Naperville to Orta Nova | 4,989.91 mi (8,030.48 km) |
| Naperville to Orte | 4,808.32 mi (7,738.24 km) |
| Naperville to Ortona | 4,892.93 mi (7,874.41 km) |
| Naperville to Orvieto | 4,786.25 mi (7,702.73 km) |
| Naperville to Orzinuovi | 4,588.00 mi (7,383.68 km) |
| Naperville to Osimo | 4,807.52 mi (7,736.95 km) |
| Naperville to Ospitaletto | 4,587.12 mi (7,382.25 km) |
| Naperville to Ostuni | 5,090.61 mi (8,192.55 km) |
| Naperville to Ottaviano | 4,962.31 mi (7,986.07 km) |
| Naperville to Ovada | 4,568.17 mi (7,351.76 km) |
| Naperville to Ozieri | 4,750.00 mi (7,644.39 km) |
| Naperville to Paceco | 5,010.34 mi (8,063.36 km) |
