| Mount Vernon to Orbetello | 4,190.48 mi (6,743.92 km) |
| Mount Vernon to Oria | 4,543.09 mi (7,311.40 km) |
| Mount Vernon to Oristano | 4,161.08 mi (6,696.61 km) |
| Mount Vernon to Orta Nova | 4,427.73 mi (7,125.74 km) |
| Mount Vernon to Orte | 4,241.28 mi (6,825.68 km) |
| Mount Vernon to Ortona | 4,333.03 mi (6,973.34 km) |
| Mount Vernon to Orvieto | 4,220.12 mi (6,791.63 km) |
| Mount Vernon to Orzinuovi | 4,035.11 mi (6,493.88 km) |
| Mount Vernon to Osimo | 4,252.70 mi (6,844.06 km) |
| Mount Vernon to Ospitaletto | 4,036.04 mi (6,495.38 km) |
| Mount Vernon to Ostuni | 4,531.90 mi (7,293.39 km) |
| Mount Vernon to Ottaviano | 4,391.56 mi (7,067.53 km) |
| Mount Vernon to Ovada | 4,004.29 mi (6,444.29 km) |
| Mount Vernon to Ozieri | 4,156.19 mi (6,688.73 km) |
| Mount Vernon to Paceco | 4,411.81 mi (7,100.13 km) |
