| Huntsville to Orbetello | 5,007.09 mi (8,058.14 km) |
| Huntsville to Oria | 5,358.33 mi (8,623.40 km) |
| Huntsville to Oristano | 4,980.32 mi (8,015.05 km) |
| Huntsville to Orta Nova | 5,243.16 mi (8,438.05 km) |
| Huntsville to Orte | 5,057.26 mi (8,138.88 km) |
| Huntsville to Ortona | 5,147.96 mi (8,284.84 km) |
| Huntsville to Orvieto | 5,035.94 mi (8,104.56 km) |
| Huntsville to Orzinuovi | 4,848.29 mi (7,802.58 km) |
| Huntsville to Osimo | 5,066.60 mi (8,153.90 km) |
| Huntsville to Ospitaletto | 4,848.86 mi (7,803.48 km) |
| Huntsville to Ostuni | 5,346.88 mi (8,604.97 km) |
| Huntsville to Ottaviano | 5,208.25 mi (8,381.87 km) |
| Huntsville to Ovada | 4,819.46 mi (7,756.18 km) |
| Huntsville to Ozieri | 4,975.08 mi (8,006.63 km) |
| Huntsville to Paceco | 5,231.06 mi (8,418.58 km) |
