| Boulder to Karlovo | 5,928.55 mi (9,541.08 km) |
| Boulder to Karnobat | 5,993.04 mi (9,644.87 km) |
| Boulder to Kavarna | 5,985.62 mi (9,632.92 km) |
| Boulder to Kazanlak | 5,947.69 mi (9,571.88 km) |
| Boulder to Knezha | 5,859.23 mi (9,429.51 km) |
| Boulder to Kostinbrod | 5,870.92 mi (9,448.34 km) |
| Boulder to Kozloduy | 5,833.08 mi (9,387.43 km) |
| Boulder to Kyustendil | 5,883.90 mi (9,469.21 km) |
| Boulder to Levski | 5,897.74 mi (9,491.50 km) |
| Boulder to Lom | 5,815.90 mi (9,359.78 km) |
| Boulder to Lovech | 5,898.43 mi (9,492.60 km) |
| Boulder to Lukovit | 5,878.39 mi (9,460.35 km) |
| Boulder to Lyaskovets | 5,929.83 mi (9,543.14 km) |
| Boulder to Mezdra | 5,867.15 mi (9,442.27 km) |
| Boulder to Momchilgrad | 6,009.06 mi (9,670.64 km) |
