| Middle River to Smolyan | 4,974.15 mi (8,005.12 km) |
| Middle River to Sofia | 4,871.82 mi (7,840.43 km) |
| Middle River to Sopot | 4,931.91 mi (7,937.13 km) |
| Middle River to Sozopol | 5,060.70 mi (8,144.40 km) |
| Middle River to Sredets | 5,043.53 mi (8,116.78 km) |
| Middle River to Stamboliyski | 4,944.45 mi (7,957.33 km) |
| Middle River to Stara Zagora | 4,977.48 mi (8,010.49 km) |
| Middle River to Svilengrad | 5,027.92 mi (8,091.65 km) |
| Middle River to Svishtov | 4,916.07 mi (7,911.65 km) |
| Middle River to Targovishte | 4,980.66 mi (8,015.59 km) |
| Middle River to Teteven | 4,901.24 mi (7,887.79 km) |
| Middle River to Troyan | 4,920.90 mi (7,919.43 km) |
| Middle River to Tryavna | 4,953.28 mi (7,971.54 km) |
| Middle River to Tutrakan | 4,948.30 mi (7,963.52 km) |
| Middle River to Varna | 5,034.96 mi (8,102.99 km) |
