| Riverdale to Smolyan | 5,570.68 mi (8,965.14 km) |
| Riverdale to Sofia | 5,468.34 mi (8,800.44 km) |
| Riverdale to Sopot | 5,528.37 mi (8,897.04 km) |
| Riverdale to Sozopol | 5,656.85 mi (9,103.82 km) |
| Riverdale to Sredets | 5,639.78 mi (9,076.36 km) |
| Riverdale to Stamboliyski | 5,540.97 mi (8,917.32 km) |
| Riverdale to Stara Zagora | 5,573.90 mi (8,970.33 km) |
| Riverdale to Svilengrad | 5,624.38 mi (9,051.57 km) |
| Riverdale to Svishtov | 5,512.26 mi (8,871.12 km) |
| Riverdale to Targovishte | 5,576.75 mi (8,974.91 km) |
| Riverdale to Teteven | 5,497.70 mi (8,847.70 km) |
| Riverdale to Troyan | 5,517.33 mi (8,879.29 km) |
| Riverdale to Tryavna | 5,549.64 mi (8,931.28 km) |
| Riverdale to Tutrakan | 5,544.09 mi (8,922.35 km) |
| Riverdale to Varna | 5,630.79 mi (9,061.89 km) |
