Żuławy Wiślane, in English known as the Vistula Fens, is the alluvial delta area of the river Vistula, in the northern part of Poland. It is a flat and deforested region comprising wetlands and agricultural plains that cover approximately 1,700 squared kilometres, with much of the land being situated below sea level. Poland's lowest point is located at Raczki Elbląskie in the Żuławy region.