| Northolt to Karlovo | 1,325.19 mi (2,132.68 km) |
| Northolt to Karnobat | 1,415.32 mi (2,277.74 km) |
| Northolt to Kavarna | 1,440.78 mi (2,318.72 km) |
| Northolt to Kazanlak | 1,350.60 mi (2,173.57 km) |
| Northolt to Knezha | 1,261.06 mi (2,029.48 km) |
| Northolt to Kostinbrod | 1,253.28 mi (2,016.96 km) |
| Northolt to Kozloduy | 1,235.55 mi (1,988.43 km) |
| Northolt to Kyustendil | 1,254.39 mi (2,018.74 km) |
| Northolt to Levski | 1,309.65 mi (2,107.69 km) |
| Northolt to Lom | 1,213.48 mi (1,952.91 km) |
| Northolt to Lovech | 1,301.64 mi (2,094.78 km) |
| Northolt to Lukovit | 1,276.40 mi (2,054.16 km) |
| Northolt to Lyaskovets | 1,344.29 mi (2,163.43 km) |
| Northolt to Mezdra | 1,259.29 mi (2,026.63 km) |
| Northolt to Momchilgrad | 1,396.63 mi (2,247.66 km) |
