The Wieprz (Polish pronunciation:[ˈvjɛpʂ], boar) is a river in central-eastern Poland, a tributary of the Vistula. It is the country's ninth longest river, with a total length of 303km and a catchment area of 10,415km², all within Poland. Its course near the town of Łęczna includes the protected area known as Wieprz Landscape Park.