| South Houston to Devnya | 6,234.79 mi (10,033.92 km) |
| South Houston to Dimitrovgrad | 6,215.33 mi (10,002.60 km) |
| South Houston to Dobrich | 6,228.01 mi (10,023.01 km) |
| South Houston to Dospat | 6,178.10 mi (9,942.69 km) |
| South Houston to Dupnitsa | 6,109.55 mi (9,832.37 km) |
| South Houston to Elhovo | 6,246.71 mi (10,053.11 km) |
| South Houston to Etropole | 6,118.30 mi (9,846.45 km) |
| South Houston to Gabrovo | 6,167.67 mi (9,925.90 km) |
| South Houston to Gorna Oryahovitsa | 6,169.26 mi (9,928.46 km) |
| South Houston to Gotse Delchev | 6,164.86 mi (9,921.39 km) |
| South Houston to Harmanli | 6,232.18 mi (10,029.73 km) |
| South Houston to Haskovo | 6,219.42 mi (10,009.18 km) |
| South Houston to Ihtiman | 6,129.02 mi (9,863.70 km) |
| South Houston to Isperih | 6,184.33 mi (9,952.72 km) |
| South Houston to Kardzhali | 6,224.73 mi (10,017.73 km) |
