| Serres to Oerlinghausen | 1,028.61 mi (1,655.39 km) |
| Serres to Oestrich-Winkel | 969.19 mi (1,559.76 km) |
| Serres to Offenburg | 917.57 mi (1,476.68 km) |
| Serres to Oftersheim | 923.55 mi (1,486.31 km) |
| Serres to Ohrdruf | 909.79 mi (1,464.16 km) |
| Serres to Ohringen | 882.62 mi (1,420.44 km) |
| Serres to Olbernhau | 822.98 mi (1,324.45 km) |
| Serres to Olching | 775.22 mi (1,247.59 km) |
| Serres to Oldenburg | 1,097.33 mi (1,765.98 km) |
| Serres to Oldenburg in Holstein | 1,083.07 mi (1,743.04 km) |
| Serres to Olfen | 1,060.07 mi (1,706.01 km) |
| Serres to Olpe | 1,015.47 mi (1,634.24 km) |
| Serres to Olsberg | 1,007.25 mi (1,621.01 km) |
| Serres to Oranienburg | 939.77 mi (1,512.42 km) |
| Serres to Ortenberg | 945.29 mi (1,521.30 km) |
