The Vanni, also spelled Wanni, is the name given to the mainland area of the Northern Province of Sri Lanka.
Tamil feudal chiefs called Vanniar chiefs who have their origin here cultivated the Vanni in the first millennium of the Common Era governing what were called Vannimai, the Jaffna Kingdom's land divisions located south of the Jaffna Peninsula in the present-day Northern, North Central and Eastern provinces of Sri Lanka.
Geographically, the Vanni is distinct from the Jaffna Peninsula, the other area of the Northern Province.
Much of the interior (approximately 4,200 km2 (1,600 sq mi)) of the Vanni is covered by dense forest.
However, the area's population figures have been highly volatile due to massive displacement caused by the Sri Lankan Civil War.