Asipatravana is one of the eighteen kinds of Naraka (hell). While going to Yamaloka (the abode of Yama,that is, the world of the dead), crossing the river Vaitaraṇī (Vaitarani), one has to enter into this Asipatravana. It is imagined that the leaves of the trees of this vana(forest) are as sharp as swords. The moment one comes here, one gets scratched by these sword-like leaves. That is why this forest is called Asipatra (Asi is word, patra is leaf).