San - one of the main rivers in Poland, with a length of 457 km. The San has its sources in Ukraine but flows only a little over a kilometre there, continuing for more than 50 km as a border river. The source of the San is in the Bieszczady...
The Bug - one of the major rivers in Poland, measuring 772 km in length, of which 363 km serve as a border river. Following the Vistula, Odra, and Warta, it is the fourth longest river in Poland. The source of the Bug is located in Ukraine in...
