The Tisa river is the longest tributary of the Danube, with a total length of 966 km. It originates in Ukraine in the western Carpathians from the merging of the Black Tisa and White Tisa rivers. It flows through Ukraine, Slovakia, Romania, Hungary and Serbia. It flows into the Danube near Stari Slankamen.
When river levels are favourable, the Tisa can be navigated along a length of around 690 km, from its confluence with the Danube to Vásárosnamény in Hungary. The Serbian section of the Tisa is 168 km long, from its confluence with the Danube to the Serbia-Hungary border, which is some 17% of its total length. The largest tributary of the Tisa is the Mureş, followed by the Begej, Bodrog, Zlatica, the Kereš or Körös, the Szamos and the Sajó. The Bački Kanal connects the Tisa with the Danube and the Begejski Kanal with the Tamiš. Important towns on the Tisa are Tokaj, Szolnok, Csongrád, Szeged, Senta and Bečej.
The Tisa forms a natural boundary between the districts of Bačka on the right bank and Banat on the left, and since it also touches on the third Vojvodina district of Srem, at the confluence at Stari Slankamen, it is a true Vojvodinian river.
Because of its width and snaking course, the Tisa was in earlier times often spoken of with awe and admiration. It is mentioned in numerous stories and poems, and according to legend also conceals the secret burial place of Attila the Hun.