| Houghton Regis to Oerlinghausen | 391.31 mi (629.76 km) |
| Houghton Regis to Oestrich-Winkel | 393.40 mi (633.11 km) |
| Houghton Regis to Offenburg | 442.77 mi (712.57 km) |
| Houghton Regis to Oftersheim | 435.48 mi (700.83 km) |
| Houghton Regis to Ohrdruf | 490.77 mi (789.82 km) |
| Houghton Regis to Ohringen | 477.59 mi (768.60 km) |
| Houghton Regis to Olbernhau | 603.98 mi (972.01 km) |
| Houghton Regis to Olching | 583.43 mi (938.93 km) |
| Houghton Regis to Oldenburg | 376.95 mi (606.65 km) |
| Houghton Regis to Oldenburg in Holstein | 500.68 mi (805.77 km) |
| Houghton Regis to Olfen | 337.90 mi (543.79 km) |
| Houghton Regis to Olpe | 364.78 mi (587.05 km) |
| Houghton Regis to Olsberg | 388.01 mi (624.44 km) |
| Houghton Regis to Oranienburg | 583.14 mi (938.47 km) |
| Houghton Regis to Ortenberg | 428.59 mi (689.74 km) |
