| South Portland to Karlovo | 4,501.88 mi (7,245.08 km) |
| South Portland to Karnobat | 4,589.58 mi (7,386.22 km) |
| South Portland to Kavarna | 4,608.35 mi (7,416.42 km) |
| South Portland to Kazanlak | 4,526.91 mi (7,285.35 km) |
| South Portland to Knezha | 4,437.06 mi (7,140.76 km) |
| South Portland to Kostinbrod | 4,430.21 mi (7,129.73 km) |
| South Portland to Kozloduy | 4,411.34 mi (7,099.37 km) |
| South Portland to Kyustendil | 4,430.36 mi (7,129.97 km) |
| South Portland to Levski | 4,484.68 mi (7,217.39 km) |
| South Portland to Lom | 4,389.69 mi (7,064.53 km) |
| South Portland to Lovech | 4,477.70 mi (7,206.16 km) |
| South Portland to Lukovit | 4,452.84 mi (7,166.15 km) |
| South Portland to Lyaskovets | 4,519.20 mi (7,272.94 km) |
| South Portland to Mezdra | 4,436.07 mi (7,139.17 km) |
| South Portland to Momchilgrad | 4,573.55 mi (7,360.41 km) |
