WARTA, a river of Poland and Germany, and the chief affluent of the river Oder. It rises in the Carpathian mountains. Its total length is 445 m. and it is navigable up to Konin in %Vest Poland, a distance of 265 m. Its banks are mostly low and flat, its lower course especially running through drained and cul tivated marshes. It is connected with the Vistula through its tributary the Notec and the Bydgoszcz canal. The area of its drainage basin is 17,400 sq.m.