| Gaithersburg to Smolyan | 5,015.81 mi (8,072.17 km) |
| Gaithersburg to Sofia | 4,913.39 mi (7,907.34 km) |
| Gaithersburg to Sopot | 4,973.31 mi (8,003.76 km) |
| Gaithersburg to Sozopol | 5,101.74 mi (8,210.46 km) |
| Gaithersburg to Sredets | 5,084.67 mi (8,182.98 km) |
| Gaithersburg to Stamboliyski | 4,986.00 mi (8,024.20 km) |
| Gaithersburg to Stara Zagora | 5,018.82 mi (8,077.00 km) |
| Gaithersburg to Svilengrad | 5,069.33 mi (8,158.30 km) |
| Gaithersburg to Svishtov | 4,957.15 mi (7,977.76 km) |
| Gaithersburg to Targovishte | 5,021.66 mi (8,081.57 km) |
| Gaithersburg to Teteven | 4,942.64 mi (7,954.42 km) |
| Gaithersburg to Troyan | 4,962.25 mi (7,985.97 km) |
| Gaithersburg to Tryavna | 4,994.53 mi (8,037.92 km) |
| Gaithersburg to Tutrakan | 4,989.09 mi (8,029.16 km) |
| Gaithersburg to Varna | 5,075.78 mi (8,168.68 km) |
