| Boulder City to Karlovo | 6,449.47 mi (10,379.42 km) |
| Boulder City to Karnobat | 6,506.85 mi (10,471.76 km) |
| Boulder City to Kavarna | 6,492.45 mi (10,448.59 km) |
| Boulder City to Kazanlak | 6,466.78 mi (10,407.28 km) |
| Boulder City to Knezha | 6,379.93 mi (10,267.51 km) |
| Boulder City to Kostinbrod | 6,396.31 mi (10,293.87 km) |
| Boulder City to Kozloduy | 6,354.04 mi (10,225.83 km) |
| Boulder City to Kyustendil | 6,412.45 mi (10,319.84 km) |
| Boulder City to Levski | 6,415.50 mi (10,324.76 km) |
| Boulder City to Lom | 6,338.26 mi (10,200.45 km) |
| Boulder City to Lovech | 6,418.20 mi (10,329.10 km) |
| Boulder City to Lukovit | 6,399.71 mi (10,299.34 km) |
| Boulder City to Lyaskovets | 6,446.48 mi (10,374.61 km) |
| Boulder City to Mezdra | 6,390.08 mi (10,283.84 km) |
| Boulder City to Momchilgrad | 6,531.22 mi (10,510.98 km) |
