| Allentown to Oerlinghausen | 3,863.99 mi (6,218.49 km) |
| Allentown to Oestrich-Winkel | 3,894.25 mi (6,267.19 km) |
| Allentown to Offenburg | 3,937.08 mi (6,336.12 km) |
| Allentown to Oftersheim | 3,936.51 mi (6,335.19 km) |
| Allentown to Ohrdruf | 3,978.06 mi (6,402.07 km) |
| Allentown to Ohringen | 3,978.74 mi (6,403.17 km) |
| Allentown to Olbernhau | 4,084.43 mi (6,573.26 km) |
| Allentown to Olching | 4,083.98 mi (6,572.54 km) |
| Allentown to Oldenburg | 3,813.86 mi (6,137.81 km) |
| Allentown to Oldenburg in Holstein | 3,881.69 mi (6,246.97 km) |
| Allentown to Olfen | 3,820.90 mi (6,149.15 km) |
| Allentown to Olpe | 3,858.28 mi (6,209.30 km) |
| Allentown to Olsberg | 3,874.40 mi (6,235.25 km) |
| Allentown to Oranienburg | 4,014.81 mi (6,461.22 km) |
| Allentown to Ortenberg | 3,926.01 mi (6,318.31 km) |
