Kishtwar has been referred to as Kasthavata in Rajatrangini, which is a metrical historical chronicle of north-western Indian subcontinent, particularly the kings of Kashmir, written in Sanskrit by Kashmiri Brahman Kalhana in 12th century CE.
It was called so during the reign of Raja Kalsa of Kashmir (A.D. 1063-89).
An interesting point to note about the place is the fact that the patron saint of Kishtwar is Hazrat Shah Farid-ud-Din Baghdadi — a Sufi saint who is known to have spread Islam in this area — whose shrine is revered equally by Muslims and Hindus.