| Fort Madison to Oerlinghausen | 4,452.39 mi (7,165.44 km) |
| Fort Madison to Oestrich-Winkel | 4,504.86 mi (7,249.87 km) |
| Fort Madison to Offenburg | 4,562.66 mi (7,342.88 km) |
| Fort Madison to Oftersheim | 4,551.10 mi (7,324.29 km) |
| Fort Madison to Ohrdruf | 4,570.45 mi (7,355.42 km) |
| Fort Madison to Ohringen | 4,591.58 mi (7,389.44 km) |
| Fort Madison to Olbernhau | 4,668.38 mi (7,513.04 km) |
| Fort Madison to Olching | 4,699.25 mi (7,562.71 km) |
| Fort Madison to Oldenburg | 4,391.47 mi (7,067.39 km) |
| Fort Madison to Oldenburg in Holstein | 4,437.49 mi (7,141.44 km) |
| Fort Madison to Olfen | 4,416.40 mi (7,107.51 km) |
| Fort Madison to Olpe | 4,459.35 mi (7,176.63 km) |
| Fort Madison to Olsberg | 4,469.78 mi (7,193.42 km) |
| Fort Madison to Oranienburg | 4,578.23 mi (7,367.95 km) |
| Fort Madison to Ortenberg | 4,529.29 mi (7,289.18 km) |
