| Upper Montclair to Orbetello | 4,209.45 mi (6,774.45 km) |
| Upper Montclair to Oria | 4,561.94 mi (7,341.74 km) |
| Upper Montclair to Oristano | 4,180.41 mi (6,727.72 km) |
| Upper Montclair to Orta Nova | 4,446.59 mi (7,156.10 km) |
| Upper Montclair to Orte | 4,260.19 mi (6,856.12 km) |
| Upper Montclair to Ortona | 4,351.85 mi (7,003.63 km) |
| Upper Montclair to Orvieto | 4,239.02 mi (6,822.04 km) |
| Upper Montclair to Orzinuovi | 4,053.79 mi (6,523.94 km) |
| Upper Montclair to Osimo | 4,271.44 mi (6,874.22 km) |
| Upper Montclair to Ospitaletto | 4,054.69 mi (6,525.39 km) |
| Upper Montclair to Ostuni | 4,550.73 mi (7,323.70 km) |
| Upper Montclair to Ottaviano | 4,410.54 mi (7,098.07 km) |
| Upper Montclair to Ovada | 4,023.13 mi (6,474.60 km) |
| Upper Montclair to Ozieri | 4,175.44 mi (6,719.72 km) |
| Upper Montclair to Paceco | 4,431.15 mi (7,131.25 km) |
