Originally the Khas are the mountain wellers living in south shadow of Himalayan range from Kashmir to Bhutan mostly Himanchal Paredsh, Utrakhand Nepal, North Bengal Sikkim and Bhutan, (specially the parts of then Greater Nepal) this Indo-Iranian Aryans tribes is believed to be are product of the union between the khas males and indigenous ethnic females(Prof Dor Bahadur Bista).According to Prof Surya Mani Adhikari(Ref KHAS KINGDOM), who settled a vast expanse of the western, central, and eastern Himalayas as early as the 2nd millennium B.C.