| Upper Montclair to Oerlinghausen | 3,802.95 mi (6,120.26 km) |
| Upper Montclair to Oestrich-Winkel | 3,831.94 mi (6,166.91 km) |
| Upper Montclair to Offenburg | 3,873.93 mi (6,234.48 km) |
| Upper Montclair to Oftersheim | 3,873.94 mi (6,234.51 km) |
| Upper Montclair to Ohrdruf | 3,916.70 mi (6,303.32 km) |
| Upper Montclair to Ohringen | 3,916.24 mi (6,302.59 km) |
| Upper Montclair to Olbernhau | 4,023.46 mi (6,475.14 km) |
| Upper Montclair to Olching | 4,021.28 mi (6,471.62 km) |
| Upper Montclair to Oldenburg | 3,753.49 mi (6,040.67 km) |
| Upper Montclair to Oldenburg in Holstein | 3,822.55 mi (6,151.81 km) |
| Upper Montclair to Olfen | 3,759.50 mi (6,050.33 km) |
| Upper Montclair to Olpe | 3,796.52 mi (6,109.92 km) |
| Upper Montclair to Olsberg | 3,812.96 mi (6,136.36 km) |
| Upper Montclair to Oranienburg | 3,955.09 mi (6,365.11 km) |
| Upper Montclair to Ortenberg | 3,864.08 mi (6,218.64 km) |
