| Middlesex to Orbetello | 4,232.74 mi (6,811.94 km) |
| Middlesex to Oria | 4,585.36 mi (7,379.42 km) |
| Middlesex to Oristano | 4,203.21 mi (6,764.41 km) |
| Middlesex to Orta Nova | 4,470.00 mi (7,193.77 km) |
| Middlesex to Orte | 4,283.55 mi (6,893.71 km) |
| Middlesex to Ortona | 4,375.30 mi (7,041.37 km) |
| Middlesex to Orvieto | 4,262.39 mi (6,859.65 km) |
| Middlesex to Orzinuovi | 4,077.37 mi (6,561.89 km) |
| Middlesex to Osimo | 4,294.97 mi (6,912.08 km) |
| Middlesex to Ospitaletto | 4,078.29 mi (6,563.37 km) |
| Middlesex to Ostuni | 4,574.17 mi (7,361.42 km) |
| Middlesex to Ottaviano | 4,433.82 mi (7,135.54 km) |
| Middlesex to Ovada | 4,046.56 mi (6,512.32 km) |
| Middlesex to Ozieri | 4,198.36 mi (6,756.61 km) |
| Middlesex to Paceco | 4,453.95 mi (7,167.93 km) |
