| Langley Park to Oerlinghausen | 3,998.07 mi (6,434.27 km) |
| Langley Park to Oestrich-Winkel | 4,027.12 mi (6,481.02 km) |
| Langley Park to Offenburg | 4,068.95 mi (6,548.34 km) |
| Langley Park to Oftersheim | 4,069.09 mi (6,548.57 km) |
| Langley Park to Ohrdruf | 4,111.86 mi (6,617.41 km) |
| Langley Park to Ohringen | 4,111.40 mi (6,616.67 km) |
| Langley Park to Olbernhau | 4,218.57 mi (6,789.13 km) |
| Langley Park to Olching | 4,216.41 mi (6,785.65 km) |
| Langley Park to Oldenburg | 3,948.46 mi (6,354.43 km) |
| Langley Park to Oldenburg in Holstein | 4,017.06 mi (6,464.83 km) |
| Langley Park to Olfen | 3,954.67 mi (6,364.42 km) |
| Langley Park to Olpe | 3,991.72 mi (6,424.05 km) |
| Langley Park to Olsberg | 4,008.13 mi (6,450.46 km) |
| Langley Park to Oranienburg | 4,149.84 mi (6,678.53 km) |
| Langley Park to Ortenberg | 4,059.28 mi (6,532.78 km) |
