| Glen Carbon to Smolyan | 5,534.36 mi (8,906.69 km) |
| Glen Carbon to Sofia | 5,430.33 mi (8,739.27 km) |
| Glen Carbon to Sopot | 5,485.05 mi (8,827.33 km) |
| Glen Carbon to Sozopol | 5,603.02 mi (9,017.19 km) |
| Glen Carbon to Sredets | 5,588.42 mi (8,993.70 km) |
| Glen Carbon to Stamboliyski | 5,501.82 mi (8,854.32 km) |
| Glen Carbon to Stara Zagora | 5,528.34 mi (8,897.01 km) |
| Glen Carbon to Svilengrad | 5,580.77 mi (8,981.38 km) |
| Glen Carbon to Svishtov | 5,460.41 mi (8,787.67 km) |
| Glen Carbon to Targovishte | 5,522.30 mi (8,887.28 km) |
| Glen Carbon to Teteven | 5,454.60 mi (8,778.33 km) |
| Glen Carbon to Troyan | 5,472.66 mi (8,807.39 km) |
| Glen Carbon to Tryavna | 5,501.94 mi (8,854.52 km) |
| Glen Carbon to Tutrakan | 5,484.49 mi (8,826.44 km) |
| Glen Carbon to Varna | 5,571.15 mi (8,965.90 km) |
