1. They are the eastern off-shoot of Himalayas.
2. It extended in the north-eastern states of India.
3. Most of these hills are located along the border of India and Myanmar while others are inside India.
4. Dafla Hills, Abor Hills, Mishmi Hills, Patkai Bum Hills, Naga Hills, Manipur Hills, Mizo Hills, Tripura Hills, Mikir Hills, Garo Hills, Khasi Hills and Jaintia Hills are the hills which are collectively known as Purvanchal Hills.