| Prospect Heights to Oberkirch | 4,366.26 mi (7,026.81 km) |
| Prospect Heights to Obernburg am Main | 4,354.91 mi (7,008.56 km) |
| Prospect Heights to Obernkirchen | 4,260.88 mi (6,857.23 km) |
| Prospect Heights to Oberschleissheim | 4,508.03 mi (7,254.97 km) |
| Prospect Heights to Oberstdorf | 4,493.99 mi (7,232.38 km) |
| Prospect Heights to Obertraubling | 4,500.80 mi (7,243.34 km) |
| Prospect Heights to Obertshausen | 4,334.79 mi (6,976.16 km) |
| Prospect Heights to Oberursel | 4,320.10 mi (6,952.52 km) |
| Prospect Heights to Ochsenfurt | 4,396.37 mi (7,075.28 km) |
| Prospect Heights to Ochsenhausen | 4,454.79 mi (7,169.30 km) |
| Prospect Heights to Ochtrup | 4,194.48 mi (6,750.36 km) |
| Prospect Heights to Odenthal | 4,235.13 mi (6,815.79 km) |
| Prospect Heights to Oelde | 4,242.72 mi (6,827.99 km) |
| Prospect Heights to Oelsnitz | 4,441.71 mi (7,148.25 km) |
| Prospect Heights to Oer-Erkenschwick | 4,217.42 mi (6,787.29 km) |
