The river Warta (/ˈvɑːrtə/ VAR-tə, Polish: [ˈvarta] ⓘ; German: Warthe [ˈvaʁtə] ⓘ; Latin: Varta) 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.

[1] Its drainage basin covers 54,529 square kilometers (21,054 sq mi).

[1] The Warta is navigable from Kostrzyn nad Odrą to Konin - approximately half of its length.

The Warta rises in the Kraków-Częstochowa Upland at Kromołów in Zawiercie, Silesian Voivodeship, flows through Łódź Land, Greater Poland and Lubusz Land, where it empties into the Oder near Kostrzyn at the border with Germany.

The river is also mentioned in the second stanza of the Polish national anthem, "Poland Is Not Yet Lost".