| Hackettstown to Oberkirch | 3,903.48 mi (6,282.04 km) |
| Hackettstown to Obernburg am Main | 3,907.33 mi (6,288.24 km) |
| Hackettstown to Obernkirchen | 3,835.81 mi (6,173.14 km) |
| Hackettstown to Oberschleissheim | 4,054.88 mi (6,525.70 km) |
| Hackettstown to Oberstdorf | 4,029.12 mi (6,484.24 km) |
| Hackettstown to Obertraubling | 4,055.97 mi (6,527.45 km) |
| Hackettstown to Obertshausen | 3,888.22 mi (6,257.49 km) |
| Hackettstown to Oberursel | 3,873.93 mi (6,234.49 km) |
| Hackettstown to Ochsenfurt | 3,950.22 mi (6,357.26 km) |
| Hackettstown to Ochsenhausen | 3,994.40 mi (6,428.36 km) |
| Hackettstown to Ochtrup | 3,762.73 mi (6,055.53 km) |
| Hackettstown to Odenthal | 3,791.94 mi (6,102.54 km) |
| Hackettstown to Oelde | 3,810.40 mi (6,132.25 km) |
| Hackettstown to Oelsnitz | 4,009.70 mi (6,452.99 km) |
| Hackettstown to Oer-Erkenschwick | 3,780.44 mi (6,084.02 km) |
