| Harpenden to Isny im Allgau | 543.70 mi (875.00 km) |
| Harpenden to Isselburg | 291.10 mi (468.48 km) |
| Harpenden to Issum | 290.84 mi (468.06 km) |
| Harpenden to Itzehoe | 436.14 mi (701.90 km) |
| Harpenden to Jena | 518.00 mi (833.64 km) |
| Harpenden to Jever | 366.03 mi (589.07 km) |
| Harpenden to Jork | 436.35 mi (702.24 km) |
| Harpenden to Juchen | 299.07 mi (481.31 km) |
| Harpenden to Julich | 295.88 mi (476.18 km) |
| Harpenden to Juterbog | 571.60 mi (919.91 km) |
| Harpenden to Kaarst | 302.38 mi (486.64 km) |
| Harpenden to Kaiserslautern | 391.58 mi (630.19 km) |
| Harpenden to Kalkar | 284.01 mi (457.08 km) |
| Harpenden to Kall | 311.36 mi (501.08 km) |
| Harpenden to Kaltenkirchen | 452.14 mi (727.65 km) |
