| Harpenden to Karlovo | 1,330.29 mi (2,140.89 km) |
| Harpenden to Karnobat | 1,419.55 mi (2,284.54 km) |
| Harpenden to Kavarna | 1,443.91 mi (2,323.74 km) |
| Harpenden to Kazanlak | 1,355.47 mi (2,181.41 km) |
| Harpenden to Knezha | 1,265.78 mi (2,037.08 km) |
| Harpenden to Kostinbrod | 1,258.93 mi (2,026.05 km) |
| Harpenden to Kozloduy | 1,240.19 mi (1,995.89 km) |
| Harpenden to Kyustendil | 1,260.70 mi (2,028.90 km) |
| Harpenden to Levski | 1,314.05 mi (2,114.76 km) |
| Harpenden to Lom | 1,218.29 mi (1,960.65 km) |
| Harpenden to Lovech | 1,306.39 mi (2,102.43 km) |
| Harpenden to Lukovit | 1,281.33 mi (2,062.10 km) |
| Harpenden to Lyaskovets | 1,348.66 mi (2,170.46 km) |
| Harpenden to Mezdra | 1,264.46 mi (2,034.96 km) |
| Harpenden to Momchilgrad | 1,402.28 mi (2,256.76 km) |
