| Middlesex to Oberkirch | 3,901.98 mi (6,279.64 km) |
| Middlesex to Obernburg am Main | 3,906.63 mi (6,287.11 km) |
| Middlesex to Obernkirchen | 3,836.30 mi (6,173.92 km) |
| Middlesex to Oberschleissheim | 4,053.80 mi (6,523.96 km) |
| Middlesex to Oberstdorf | 4,027.44 mi (6,481.54 km) |
| Middlesex to Obertraubling | 4,055.32 mi (6,526.41 km) |
| Middlesex to Obertshausen | 3,887.59 mi (6,256.47 km) |
| Middlesex to Oberursel | 3,873.32 mi (6,233.51 km) |
| Middlesex to Ochsenfurt | 3,949.56 mi (6,356.21 km) |
| Middlesex to Ochsenhausen | 3,992.98 mi (6,426.07 km) |
| Middlesex to Ochtrup | 3,762.94 mi (6,055.86 km) |
| Middlesex to Odenthal | 3,791.54 mi (6,101.90 km) |
| Middlesex to Oelde | 3,810.54 mi (6,132.47 km) |
| Middlesex to Oelsnitz | 4,009.73 mi (6,453.04 km) |
| Middlesex to Oer-Erkenschwick | 3,780.36 mi (6,083.90 km) |
