The original inhabitants of the Dooars region of Assam and North Bengal, are the Koch Rajbongshi, Mech ethnicities. The Koch and the Mech among them claim to be Kiratis as do the Bodo-Kachari people tribes of Assam. They derive their titles from the original place of their dwelling, "Koch" from the Koshi river, "Mech" from the Mechi River and "Kachari" is derived from Kachar, which means "river basin". Dhimal, Hayu, Koch, Thami, Tharu, Chepang, and Surel ethnic groups also consider themselves to be of Kirati descent.