| Boone to Smolyan | 5,332.04 mi (8,581.10 km) |
| Boone to Sofia | 5,229.58 mi (8,416.19 km) |
| Boone to Sopot | 5,289.36 mi (8,512.40 km) |
| Boone to Sozopol | 5,417.44 mi (8,718.52 km) |
| Boone to Sredets | 5,400.46 mi (8,691.20 km) |
| Boone to Stamboliyski | 5,302.17 mi (8,533.02 km) |
| Boone to Stara Zagora | 5,334.81 mi (8,585.54 km) |
| Boone to Svilengrad | 5,385.40 mi (8,666.96 km) |
| Boone to Svishtov | 5,272.88 mi (8,485.89 km) |
| Boone to Targovishte | 5,337.30 mi (8,589.55 km) |
| Boone to Teteven | 5,258.70 mi (8,463.05 km) |
| Boone to Troyan | 5,278.26 mi (8,494.54 km) |
| Boone to Tryavna | 5,310.44 mi (8,546.33 km) |
| Boone to Tutrakan | 5,304.46 mi (8,536.70 km) |
| Boone to Varna | 5,391.18 mi (8,676.27 km) |
