| Dayton to Oberkirch | 4,329.75 mi (6,968.07 km) |
| Dayton to Obernburg am Main | 4,325.63 mi (6,961.44 km) |
| Dayton to Obernkirchen | 4,241.79 mi (6,826.50 km) |
| Dayton to Oberschleissheim | 4,476.53 mi (7,204.28 km) |
| Dayton to Oberstdorf | 4,456.81 mi (7,172.55 km) |
| Dayton to Obertraubling | 4,473.23 mi (7,198.97 km) |
| Dayton to Obertshausen | 4,305.93 mi (6,929.73 km) |
| Dayton to Oberursel | 4,291.39 mi (6,906.32 km) |
| Dayton to Ochsenfurt | 4,367.89 mi (7,029.43 km) |
| Dayton to Ochsenhausen | 4,419.68 mi (7,112.78 km) |
| Dayton to Ochtrup | 4,172.11 mi (6,714.37 km) |
| Dayton to Odenthal | 4,207.57 mi (6,771.43 km) |
| Dayton to Oelde | 4,220.24 mi (6,791.82 km) |
| Dayton to Oelsnitz | 4,419.97 mi (7,113.25 km) |
| Dayton to Oer-Erkenschwick | 4,192.70 mi (6,747.50 km) |
