| Gourock to Oberkirch | 746.63 mi (1,201.58 km) |
| Gourock to Obernburg am Main | 716.85 mi (1,153.65 km) |
| Gourock to Obernkirchen | 617.84 mi (994.32 km) |
| Gourock to Oberschleissheim | 872.04 mi (1,403.42 km) |
| Gourock to Oberstdorf | 872.22 mi (1,403.71 km) |
| Gourock to Obertraubling | 859.18 mi (1,382.71 km) |
| Gourock to Obertshausen | 696.23 mi (1,120.47 km) |
| Gourock to Oberursel | 681.46 mi (1,096.71 km) |
| Gourock to Ochsenfurt | 756.61 mi (1,217.64 km) |
| Gourock to Ochsenhausen | 828.12 mi (1,332.73 km) |
| Gourock to Ochtrup | 550.30 mi (885.62 km) |
| Gourock to Odenthal | 595.56 mi (958.46 km) |
| Gourock to Oelde | 598.53 mi (963.24 km) |
| Gourock to Oelsnitz | 797.54 mi (1,283.51 km) |
| Gourock to Oer-Erkenschwick | 574.41 mi (924.43 km) |
