| Montclair to Orbetello | 6,241.83 mi (10,045.26 km) |
| Montclair to Oria | 6,551.80 mi (10,544.10 km) |
| Montclair to Oristano | 6,284.45 mi (10,113.84 km) |
| Montclair to Orta Nova | 6,446.04 mi (10,373.90 km) |
| Montclair to Orte | 6,278.97 mi (10,105.02 km) |
| Montclair to Ortona | 6,349.08 mi (10,217.85 km) |
| Montclair to Orvieto | 6,256.29 mi (10,068.52 km) |
| Montclair to Orzinuovi | 6,045.06 mi (9,728.59 km) |
| Montclair to Osimo | 6,258.87 mi (10,072.68 km) |
| Montclair to Ospitaletto | 6,041.42 mi (9,722.72 km) |
| Montclair to Ostuni | 6,537.18 mi (10,520.58 km) |
| Montclair to Ottaviano | 6,433.28 mi (10,353.36 km) |
| Montclair to Ovada | 6,042.82 mi (9,724.99 km) |
| Montclair to Ozieri | 6,263.90 mi (10,080.78 km) |
| Montclair to Paceco | 6,523.72 mi (10,498.91 km) |
