| Ostrow Mazowiecka to Smolyan | 785.91 mi (1,264.80 km) |
| Ostrow Mazowiecka to Sofia | 700.96 mi (1,128.09 km) |
| Ostrow Mazowiecka to Sopot | 713.55 mi (1,148.34 km) |
| Ostrow Mazowiecka to Sozopol | 765.98 mi (1,232.73 km) |
| Ostrow Mazowiecka to Sredets | 762.59 mi (1,227.28 km) |
| Ostrow Mazowiecka to Stamboliyski | 747.06 mi (1,202.27 km) |
| Ostrow Mazowiecka to Stara Zagora | 736.99 mi (1,186.07 km) |
| Ostrow Mazowiecka to Svilengrad | 788.15 mi (1,268.41 km) |
| Ostrow Mazowiecka to Svishtov | 653.89 mi (1,052.33 km) |
| Ostrow Mazowiecka to Targovishte | 694.05 mi (1,116.96 km) |
| Ostrow Mazowiecka to Teteven | 691.53 mi (1,112.90 km) |
| Ostrow Mazowiecka to Troyan | 697.37 mi (1,122.31 km) |
| Ostrow Mazowiecka to Tryavna | 706.10 mi (1,136.35 km) |
| Ostrow Mazowiecka to Tutrakan | 641.73 mi (1,032.76 km) |
| Ostrow Mazowiecka to Varna | 717.56 mi (1,154.80 km) |
