| Hackettstown to Orbetello | 4,236.51 mi (6,818.00 km) |
| Hackettstown to Oria | 4,588.66 mi (7,384.73 km) |
| Hackettstown to Oristano | 4,208.58 mi (6,773.06 km) |
| Hackettstown to Orta Nova | 4,473.35 mi (7,199.16 km) |
| Hackettstown to Orte | 4,287.08 mi (6,899.39 km) |
| Hackettstown to Ortona | 4,378.49 mi (7,046.50 km) |
| Hackettstown to Orvieto | 4,265.86 mi (6,865.24 km) |
| Hackettstown to Orzinuovi | 4,080.04 mi (6,566.18 km) |
| Hackettstown to Osimo | 4,297.85 mi (6,916.71 km) |
| Hackettstown to Ospitaletto | 4,080.86 mi (6,567.52 km) |
| Hackettstown to Ostuni | 4,577.39 mi (7,366.59 km) |
| Hackettstown to Ottaviano | 4,437.62 mi (7,141.66 km) |
| Hackettstown to Ovada | 4,049.81 mi (6,517.54 km) |
| Hackettstown to Ozieri | 4,203.36 mi (6,764.65 km) |
| Hackettstown to Paceco | 4,459.32 mi (7,176.59 km) |
