| Port Huron to Smolyan | 5,048.49 mi (8,124.76 km) |
| Port Huron to Sofia | 4,944.61 mi (7,957.57 km) |
| Port Huron to Sopot | 5,000.15 mi (8,046.97 km) |
| Port Huron to Sozopol | 5,119.99 mi (8,239.83 km) |
| Port Huron to Sredets | 5,104.94 mi (8,215.62 km) |
| Port Huron to Stamboliyski | 5,016.32 mi (8,072.99 km) |
| Port Huron to Stara Zagora | 5,043.84 mi (8,117.28 km) |
| Port Huron to Svilengrad | 5,096.01 mi (8,201.24 km) |
| Port Huron to Svishtov | 4,976.88 mi (8,009.51 km) |
| Port Huron to Targovishte | 5,039.29 mi (8,109.96 km) |
| Port Huron to Teteven | 4,969.65 mi (7,997.87 km) |
| Port Huron to Troyan | 4,987.96 mi (8,027.35 km) |
| Port Huron to Tryavna | 5,017.76 mi (8,075.30 km) |
| Port Huron to Tutrakan | 5,002.40 mi (8,050.58 km) |
| Port Huron to Varna | 5,089.16 mi (8,190.21 km) |
