The Warta River
Warta River, one of the longest rivers in Poland and the main tributary of the Oder River. The Warta's source is 35 miles (56 km) northwest of Kraków. The river flows north and west for some 470 miles (756 km) through drained and cultivated marshes, and into the Oder at Kostrzyn. The Warta is joined to the Vistula River by the Notec River and the Bydgoszcz Canal. It is navigable in its lower half.