| Gourock to Oerlinghausen | 612.07 mi (985.03 km) |
| Gourock to Oestrich-Winkel | 671.72 mi (1,081.04 km) |
| Gourock to Offenburg | 745.52 mi (1,199.79 km) |
| Gourock to Oftersheim | 720.60 mi (1,159.70 km) |
| Gourock to Ohrdruf | 729.77 mi (1,174.45 km) |
| Gourock to Ohringen | 758.54 mi (1,220.76 km) |
| Gourock to Olbernhau | 830.25 mi (1,336.16 km) |
| Gourock to Olching | 866.16 mi (1,393.95 km) |
| Gourock to Oldenburg | 556.10 mi (894.96 km) |
| Gourock to Oldenburg in Holstein | 629.25 mi (1,012.68 km) |
| Gourock to Olfen | 576.03 mi (927.03 km) |
| Gourock to Olpe | 620.54 mi (998.67 km) |
| Gourock to Olsberg | 629.24 mi (1,012.66 km) |
| Gourock to Oranienburg | 757.31 mi (1,218.77 km) |
| Gourock to Ortenberg | 690.84 mi (1,111.81 km) |
