| Castleton to Smolyan | 1,488.13 mi (2,394.92 km) |
| Castleton to Sofia | 1,384.28 mi (2,227.78 km) |
| Castleton to Sopot | 1,440.70 mi (2,318.59 km) |
| Castleton to Sozopol | 1,565.54 mi (2,519.49 km) |
| Castleton to Sredets | 1,548.97 mi (2,492.83 km) |
| Castleton to Stamboliyski | 1,456.10 mi (2,343.37 km) |
| Castleton to Stara Zagora | 1,485.13 mi (2,390.09 km) |
| Castleton to Svilengrad | 1,536.73 mi (2,473.12 km) |
| Castleton to Svishtov | 1,421.16 mi (2,287.14 km) |
| Castleton to Targovishte | 1,485.28 mi (2,390.33 km) |
| Castleton to Teteven | 1,410.11 mi (2,269.36 km) |
| Castleton to Troyan | 1,428.90 mi (2,299.60 km) |
| Castleton to Tryavna | 1,459.88 mi (2,349.45 km) |
| Castleton to Tutrakan | 1,452.57 mi (2,337.69 km) |
| Castleton to Varna | 1,539.22 mi (2,477.13 km) |
