| South Houston to Karlovo | 6,157.83 mi (9,910.07 km) |
| South Houston to Karnobat | 6,240.58 mi (10,043.25 km) |
| South Houston to Kavarna | 6,252.54 mi (10,062.49 km) |
| South Houston to Kazanlak | 6,181.66 mi (9,948.43 km) |
| South Houston to Knezha | 6,091.45 mi (9,803.25 km) |
| South Houston to Kostinbrod | 6,088.81 mi (9,799.00 km) |
| South Houston to Kozloduy | 6,065.43 mi (9,761.36 km) |
| South Houston to Kyustendil | 6,091.68 mi (9,803.61 km) |
| South Houston to Levski | 6,137.23 mi (9,876.91 km) |
| South Houston to Lom | 6,044.68 mi (9,727.97 km) |
| South Houston to Lovech | 6,132.06 mi (9,868.60 km) |
| South Houston to Lukovit | 6,108.15 mi (9,830.13 km) |
| South Houston to Lyaskovets | 6,171.42 mi (9,931.94 km) |
| South Houston to Mezdra | 6,092.55 mi (9,805.01 km) |
| South Houston to Momchilgrad | 6,232.01 mi (10,029.46 km) |
