| Castle Rock to Smolyan | 6,009.00 mi (9,670.55 km) |
| Castle Rock to Sofia | 5,905.13 mi (9,503.38 km) |
| Castle Rock to Sopot | 5,951.40 mi (9,577.84 km) |
| Castle Rock to Sozopol | 6,052.13 mi (9,739.95 km) |
| Castle Rock to Sredets | 6,041.30 mi (9,722.54 km) |
| Castle Rock to Stamboliyski | 5,973.41 mi (9,613.27 km) |
| Castle Rock to Stara Zagora | 5,990.61 mi (9,640.96 km) |
| Castle Rock to Svilengrad | 6,044.46 mi (9,727.61 km) |
| Castle Rock to Svishtov | 5,915.67 mi (9,520.36 km) |
| Castle Rock to Targovishte | 5,972.48 mi (9,611.78 km) |
| Castle Rock to Teteven | 5,921.96 mi (9,530.47 km) |
| Castle Rock to Troyan | 5,937.46 mi (9,555.41 km) |
| Castle Rock to Tryavna | 5,961.92 mi (9,594.78 km) |
| Castle Rock to Tutrakan | 5,928.45 mi (9,540.92 km) |
| Castle Rock to Varna | 6,012.92 mi (9,676.86 km) |
