| Williamstown to Smolyan | 4,899.33 mi (7,884.71 km) |
| Williamstown to Sofia | 4,797.16 mi (7,720.29 km) |
| Williamstown to Sopot | 4,857.58 mi (7,817.52 km) |
| Williamstown to Sozopol | 4,987.04 mi (8,025.87 km) |
| Williamstown to Sredets | 4,969.71 mi (7,997.98 km) |
| Williamstown to Stamboliyski | 4,869.84 mi (7,837.24 km) |
| Williamstown to Stara Zagora | 4,903.29 mi (7,891.09 km) |
| Williamstown to Svilengrad | 4,953.56 mi (7,971.99 km) |
| Williamstown to Svishtov | 4,842.36 mi (7,793.03 km) |
| Williamstown to Targovishte | 4,907.10 mi (7,897.21 km) |
| Williamstown to Teteven | 4,826.92 mi (7,768.18 km) |
| Williamstown to Troyan | 4,846.68 mi (7,799.98 km) |
| Williamstown to Tryavna | 4,879.25 mi (7,852.40 km) |
| Williamstown to Tutrakan | 4,875.15 mi (7,845.79 km) |
| Williamstown to Varna | 4,961.76 mi (7,985.18 km) |
