| Mentor to Oerlinghausen | 4,035.74 mi (6,494.89 km) |
| Mentor to Oestrich-Winkel | 4,076.45 mi (6,560.41 km) |
| Mentor to Offenburg | 4,126.46 mi (6,640.90 km) |
| Mentor to Oftersheim | 4,120.71 mi (6,631.65 km) |
| Mentor to Ohrdruf | 4,152.06 mi (6,682.10 km) |
| Mentor to Ohringen | 4,162.27 mi (6,698.52 km) |
| Mentor to Olbernhau | 4,254.92 mi (6,847.63 km) |
| Mentor to Olching | 4,268.98 mi (6,870.25 km) |
| Mentor to Oldenburg | 3,980.43 mi (6,405.89 km) |
| Mentor to Oldenburg in Holstein | 4,038.55 mi (6,499.41 km) |
| Mentor to Olfen | 3,995.79 mi (6,430.60 km) |
| Mentor to Olpe | 4,035.89 mi (6,495.14 km) |
| Mentor to Olsberg | 4,049.43 mi (6,516.92 km) |
| Mentor to Oranienburg | 4,175.66 mi (6,720.08 km) |
| Mentor to Ortenberg | 4,104.89 mi (6,606.18 km) |
