The Zasavica (Serbian Cyrillic: Засавица, pronounced [ˈzâsaʋit͜sa]) is a river in the region of Mačva, western-central Serbia. The Zasavica is a 33.1 km-long right tributary to the Sava river which entirely flows through the region of Mačva. It originates from the several streams out of the swamps north of the village of Salaš Crnobarski, in the floodplain of the lower course of the Drina river. The river flows in the north-east direction, for 10 km parallel to the flow of the Sava and next to the villages of Glogovac, Sovljak, Crna Bara, Banovo Polje and Radenković, where the river crosses the administrative border of Central Serbia and the province of Vojvodina, where it flow near the settlements of Ravnje, Zasavica I, Zasavica II, Noćaj, and Mačvanska Mitrovica. At village Banovo Polje