| Hemel Hempstead to Oerlinghausen | 389.86 mi (627.43 km) |
| Hemel Hempstead to Oestrich-Winkel | 388.32 mi (624.94 km) |
| Hemel Hempstead to Offenburg | 435.68 mi (701.17 km) |
| Hemel Hempstead to Oftersheim | 429.75 mi (691.61 km) |
| Hemel Hempstead to Ohrdruf | 487.73 mi (784.93 km) |
| Hemel Hempstead to Ohringen | 472.02 mi (759.64 km) |
| Hemel Hempstead to Olbernhau | 601.21 mi (967.56 km) |
| Hemel Hempstead to Olching | 577.48 mi (929.36 km) |
| Hemel Hempstead to Oldenburg | 377.81 mi (608.03 km) |
| Hemel Hempstead to Oldenburg in Holstein | 502.84 mi (809.24 km) |
| Hemel Hempstead to Olfen | 335.85 mi (540.50 km) |
| Hemel Hempstead to Olpe | 361.40 mi (581.61 km) |
| Hemel Hempstead to Olsberg | 385.39 mi (620.22 km) |
| Hemel Hempstead to Oranienburg | 582.94 mi (938.15 km) |
| Hemel Hempstead to Ortenberg | 424.43 mi (683.06 km) |
