| Rockford to Smolyan | 5,327.07 mi (8,573.09 km) |
| Rockford to Sofia | 5,222.84 mi (8,405.35 km) |
| Rockford to Sopot | 5,275.92 mi (8,490.77 km) |
| Rockford to Sozopol | 5,390.71 mi (8,675.50 km) |
| Rockford to Sredets | 5,376.81 mi (8,653.15 km) |
| Rockford to Stamboliyski | 5,293.81 mi (8,519.57 km) |
| Rockford to Stara Zagora | 5,318.47 mi (8,559.26 km) |
| Rockford to Svilengrad | 5,371.31 mi (8,644.28 km) |
| Rockford to Svishtov | 5,248.98 mi (8,447.43 km) |
| Rockford to Targovishte | 5,310.02 mi (8,545.65 km) |
| Rockford to Teteven | 5,245.61 mi (8,441.99 km) |
| Rockford to Troyan | 5,263.18 mi (8,470.27 km) |
| Rockford to Tryavna | 5,291.55 mi (8,515.93 km) |
| Rockford to Tutrakan | 5,270.94 mi (8,482.75 km) |
| Rockford to Varna | 5,357.37 mi (8,621.85 km) |
