| Troisdorf to Oerlinghausen | 102.78 mi (165.41 km) |
| Troisdorf to Oestrich-Winkel | 67.54 mi (108.70 km) |
| Troisdorf to Offenburg | 166.01 mi (267.17 km) |
| Troisdorf to Oftersheim | 118.26 mi (190.33 km) |
| Troisdorf to Ohrdruf | 156.13 mi (251.26 km) |
| Troisdorf to Ohringen | 152.65 mi (245.66 km) |
| Troisdorf to Olbernhau | 270.23 mi (434.89 km) |
| Troisdorf to Olching | 259.78 mi (418.07 km) |
| Troisdorf to Oldenburg | 167.02 mi (268.79 km) |
| Troisdorf to Oldenburg in Holstein | 287.07 mi (462.00 km) |
| Troisdorf to Olfen | 63.00 mi (101.39 km) |
| Troisdorf to Olpe | 32.61 mi (52.48 km) |
| Troisdorf to Olsberg | 68.42 mi (110.11 km) |
| Troisdorf to Oranienburg | 292.27 mi (470.36 km) |
| Troisdorf to Ortenberg | 89.20 mi (143.55 km) |
