| Castle Rock to Oberkirch | 5,111.79 mi (8,226.63 km) |
| Castle Rock to Obernburg am Main | 5,086.19 mi (8,185.43 km) |
| Castle Rock to Obernkirchen | 4,972.56 mi (8,002.56 km) |
| Castle Rock to Oberschleissheim | 5,241.47 mi (8,435.33 km) |
| Castle Rock to Oberstdorf | 5,239.02 mi (8,431.38 km) |
| Castle Rock to Obertraubling | 5,226.29 mi (8,410.90 km) |
| Castle Rock to Obertshausen | 5,065.51 mi (8,152.14 km) |
| Castle Rock to Oberursel | 5,050.76 mi (8,128.41 km) |
| Castle Rock to Ochsenfurt | 5,125.38 mi (8,248.50 km) |
| Castle Rock to Ochsenhausen | 5,196.29 mi (8,362.63 km) |
| Castle Rock to Ochtrup | 4,914.16 mi (7,908.58 km) |
| Castle Rock to Odenthal | 4,964.81 mi (7,990.10 km) |
| Castle Rock to Oelde | 4,961.82 mi (7,985.27 km) |
| Castle Rock to Oelsnitz | 5,155.94 mi (8,297.69 km) |
| Castle Rock to Oer-Erkenschwick | 4,941.58 mi (7,952.71 km) |
