Assam is a mini-India if not more. The human landscape is a colourful as her physiography . This land has been the meeting ground of diverse ethnic groups and cultural streams since time immemorial. Throughout history, people of different stocks have been migrating into this land and merged into a common harmonious whole in a process of assimilation and fraternization not be seen much elsewhere in India.
The principal migrants have been the Austro-Asiatics, the Dravidians, the Tibeto-Burmans, the Mongoloids and the Aryans. The Austro-Asiatics, who were one of the earliest to arrive, initially lived in the Brahmaputra Valley, but were later pushed to the hills by the subsequent waves of migrants. The Khasis and Jaintias of present-day Meghalaya are said to be the descendants of this stock.
Next to come were the Dravidians, and the ethnological conjecture is that the Kaibarta ND Bania communities of modern Assam are descendants of this group.
The Mongoloid migration to Assam took place at long intervals and from widely varied sources. They, in general, belong to the Tibeto-Burman family of the Indo-Chinese group. The early waves of this group constituted the ancestors of the present-day Kacharis, Dimasas, Bodos, Rabhas and Lahungs, as also most of the tribes living in the hills neighbouring modern Assam.
The Kacharis are a powerful family and are today mostly known as the Bodos in the Brahmaputra Valley and Dimasas in the North Cachar Hills. The Koches on the other hand are said to be an admixture of the Dravidian and Mongoloid stocks. They are called Rajbangshis in the extreme western part of the State.
The Chutiyas in Upper Assam originally settled in the north- eastern tip of the region, but later gave way to make room for the Ahoms, who belonged to the Shan sub-section of the great Indo-chinese family.
The Mishings and the Karbis belong to the Tibeto-Burman stock, and inhabit the northern plains of Upper Assam and the Karbi Hills respectively. The Khamtis of extreme Upper Assam, an also the Naras, phakiyals and Shyams (Man-Tai and Tai-Turung) belong to the Shan sub-section, and are believed to be group who arrived much after the Ahoms.
Assam today has 16 Scheduled Castes and 23 Scheduled Tribes, with proposals for inclusion of more ethnic groups in the two categories still awaiting approval of the Centre.