| Niagara Falls to Smolyan | 4,912.50 mi (7,905.91 km) |
| Niagara Falls to Sofia | 4,808.93 mi (7,739.23 km) |
| Niagara Falls to Sopot | 4,865.79 mi (7,830.74 km) |
| Niagara Falls to Sozopol | 4,988.27 mi (8,027.85 km) |
| Niagara Falls to Sredets | 4,972.61 mi (8,002.65 km) |
| Niagara Falls to Stamboliyski | 4,880.98 mi (7,855.17 km) |
| Niagara Falls to Stara Zagora | 4,910.05 mi (7,901.97 km) |
| Niagara Falls to Svilengrad | 4,961.80 mi (7,985.24 km) |
| Niagara Falls to Svishtov | 4,844.57 mi (7,796.59 km) |
| Niagara Falls to Targovishte | 4,907.67 mi (7,898.14 km) |
| Niagara Falls to Teteven | 4,835.21 mi (7,781.51 km) |
| Niagara Falls to Troyan | 4,853.92 mi (7,811.63 km) |
| Niagara Falls to Tryavna | 4,884.47 mi (7,860.79 km) |
| Niagara Falls to Tutrakan | 4,872.04 mi (7,840.79 km) |
| Niagara Falls to Varna | 4,958.87 mi (7,980.53 km) |
