Kosacha (Bulgarian: Косача, also transliterated Kosača) is a village in western Bulgaria.

The village is a conglomeration of neighborhoods scattered over hills and valleys.

The neighborhoods are Tyutyundzhiyska, Polyana, Domishlyarska - there is the house of Georgi Parvanov's mother, Evreyska (Jewish), Velichkova - there is his father's house, Eleninska / grandmother Elena hid Levski in the church, wife of grandfather Pene - a merchant in Constantinople.

The ancient town of Buieridava was located near the village and the Lobosh dam (Pchelina).

The name derives from the Bulgarian word Kosach, which means Mower.