The river Warta rises in central Poland and meanders greatly through the Polish Plain in a north-westerly direction to flow into the Oder at Kostrzyn nad Odrą on Poland's border with Germany. About 808.2 kilometres (502.2 mi) long, it the second-longest river within the borders of Poland, and the third-longest Polish river after the Oder. Its drainage basin covers 54,529 square kilometers (21,054 sq mi). The Warta is navigable from Kostrzyn nad Odrą to Konin - approximately half of its length.