| Rock Island to Smolyan | 5,420.64 mi (8,723.68 km) |
| Rock Island to Sofia | 5,316.40 mi (8,555.92 km) |
| Rock Island to Sopot | 5,369.23 mi (8,640.95 km) |
| Rock Island to Sozopol | 5,483.50 mi (8,824.84 km) |
| Rock Island to Sredets | 5,469.73 mi (8,802.68 km) |
| Rock Island to Stamboliyski | 5,387.29 mi (8,670.00 km) |
| Rock Island to Stara Zagora | 5,411.68 mi (8,709.25 km) |
| Rock Island to Svilengrad | 5,464.56 mi (8,794.36 km) |
| Rock Island to Svishtov | 5,341.94 mi (8,597.03 km) |
| Rock Island to Targovishte | 5,402.82 mi (8,695.00 km) |
| Rock Island to Teteven | 5,338.95 mi (8,592.21 km) |
| Rock Island to Troyan | 5,356.45 mi (8,620.37 km) |
| Rock Island to Tryavna | 5,384.67 mi (8,665.80 km) |
| Rock Island to Tutrakan | 5,363.52 mi (8,631.75 km) |
| Rock Island to Varna | 5,449.90 mi (8,770.77 km) |
