The Warta (Polish pronunciation: [ˈvaɾta] ; ) is a river in western-central Poland, a tributary of the Oder river. With a length of approximately it is the country's third longest river. The Warta has a basin area of 54,529 square kilometers, and it is navigable from Kostrzyn nad Odrą to Konin, approximately half of its length. It is connected to the Vistula by the river Noteć and the Bydgoszcz Canal (Kanał Bydgoski) near Bydgoszcz.