| Round Rock to Karlovo | 6,202.87 mi (9,982.56 km) |
| Round Rock to Karnobat | 6,282.76 mi (10,111.13 km) |
| Round Rock to Kavarna | 6,291.37 mi (10,124.98 km) |
| Round Rock to Kazanlak | 6,225.98 mi (10,019.75 km) |
| Round Rock to Knezha | 6,135.75 mi (9,874.54 km) |
| Round Rock to Kostinbrod | 6,135.56 mi (9,874.23 km) |
| Round Rock to Kozloduy | 6,109.62 mi (9,832.48 km) |
| Round Rock to Kyustendil | 6,140.16 mi (9,881.63 km) |
| Round Rock to Levski | 6,180.44 mi (9,946.45 km) |
| Round Rock to Lom | 6,089.41 mi (9,799.95 km) |
| Round Rock to Lovech | 6,176.27 mi (9,939.74 km) |
| Round Rock to Lukovit | 6,152.94 mi (9,902.20 km) |
| Round Rock to Lyaskovets | 6,214.39 mi (10,001.09 km) |
| Round Rock to Mezdra | 6,138.03 mi (9,878.20 km) |
| Round Rock to Momchilgrad | 6,278.40 mi (10,104.11 km) |
