The People of Assam inhabit a multi-ethnic, multi-linguistic and multi-religious society. They speak languages that belong to four main language groups: Tibeto-Burman, Indo-Aryan, Tai-Kadai, and Austroasiatic. The large number of ethnic and linguistic groups, the population composition, and the peopling process in the state has led to it being called an "India in miniature"."Assam is often referred to as 'India in miniature' so far its population composition and the process of peopling are concerned".

The peopling of Assam was understood in terms of racial types based on physical features, types that were drawn by colonial administrator Risley. These classifications are now considered to have little validity, and they yield inconsistent results; the current understanding is based on ethnolinguistic groups"The racial traits, reflected through the physical features of individuals, are of such a varying degree that it is perhaps safer to divide the State's population into ethnolinguistic groups". and in consonance with genetic studies.

Peopling of Assam Geographically Assam, in the middle of Northeast India, contains fertile river valleys surrounded and interspersed by mountains and hills. It is accessible from Tibet in the north (via Bum La, Se La, Tunga), across the Patkai in the Southeast (via Diphu, Kumjawng, Hpungan, Chaukam, Pangsau, More-Tamu) and from Burma across the Arakan Yoma (via An, Taungup). These passes have been gateways for migration routes from Tibet, Southeastern China and Myanmar. In the west both the Brahmaputra Valley and the Barak Valley open widely to the Gangetic plains. Assam has been populated via all these accessible points in the past. It has been estimated that there were eleven major waves and streams of ethnolinguistic migrations across these points over time."An analysis of peopling of Assam on the above ethnolinguistic basis, coupled with the scanty paleolithic, neolithic and historical evidences, reveals that there are as many as eleven waves and streams of migration into Assam. (The terms ‘wave’ and ‘stream’ are used here with specific meanings: while ‘wave’ is used to mean a migration at a particular point of time, ‘stream’ means continuity of migration for a long period, which may continue even now ever since it started, albeit with varying volume)." In recent years, a multidisciplinary approach using archaeological, historical linguistic and genetic data has been used to reconstruct population history.

There is no evidence in Assam and Northeast India of early hominid dispersal."Due to lack of evidence for early humans in Northeast India prior to the late Pleistocene..." The presence of a Paleolithic culture is contested."The presence of Paleographic cultural material in Northeast India is a debated issue in Indian prehistory. On the basis of tool typology, several assemblages have been placed within the context of 'Paleographic' in this region. One of the main problems of these Paleographic materials is that they occur in relatively younger deposits and in most cases in association with axes or adzes of Neolithic origin and pottery." An early report of the presence of Dravidian is also not supported."For some reason some scholars (e.g. Gait 1983 ) suggest an early Dravidian presence in the area as well, but I know of no linguistic evidence for this idea." The earliest culture in Assam is Neolithic; there is no evidence of Chalcolithic culture either in the Brahmaputra valley or in the surrounding hills; and state formation began only from middle of 1st millennium CE.

Prehistoric

The archaeological sites of Sarutaru in Kamrup and Daojali Hading in Dima Hasao district display Neolithic cultures. Some other Neolithic sites in Northeast include those in Arunachal Pradesh, Sadiya, Dibrugarh, Lakhimpur, Nagaon, Naga Hills, Karbi Anglong,‌ Kamrup, Garo and Khasi hills of Meghalaya, etc. The Neolithic culture discovered in Assam has East and Southeast Asian affinities of the Hoabinhian tradition."[T C Sharma], with his colleagues and students, has shaped our understanding of the prehistoric cultures in all the states of Northeast India. His doctoral dissertation was the first attempt of systematic study of the surface material kept in various museums and also the excavated material from Daojali Hading. He strongly believed that the Neolithic personality of the region had emerged under strong influence of the East and Southeast Asian Neolithic traditions, which were characterized by the earlier tradition known as Hoabinhian."

It had been suggested by linguists and ethnologists more than a hundred years ago that Austroasiatic speakers preceded Tibeto-Burman speakers—and the latest findings from genetic and linguistic studies support the early claim and suggest mechanisms how a section of the Austroasiatic speakers had shifted to Tibeto-Burman."On the Brahmaputra plain, the early Trans-Himalayans encountered the Austroasiatics, who had preceded them. The relative frequencies of the Ychromosomal haplogroup O1b1a1a (M95) in Trans-Himalayan speaking populations of the Indian subcontinent (Sahoo et al. 2006, Reddy et al. 2007, Gaziet al. 2013) suggest that a subset of the paternal ancestors of some Trans-Himalayan populations in northeastern India, e.g. certain Bodo-Koch communities, may originally have been Austroasiatic speakers with matriarchal, matrilinear or matrilocal societies, who were linguistically assimilated by Trans-Himalayans, providing a molecular genetic correlate for the ancient process of creolisation argued for by DeLancey (2014)"

Austroasiatic The earliest inhabitants of Assam are estimated to be late Neolithic Austroasiatic peoples who came from Southeast Asia."The peopling of Assam was first started with a wave of migration of the Australoids or Austro-Asiatic speaking people from south-east Asia..." Genetic studies on O2a1‐M95 Y-chromosomal haplogroup, which has been associated with Austroasiatic speakers in India,"The origins of Indian Austro Asiatic speakers had earlier been correlated to the origin of O2a1-M95 (Kumar et al., 2007)." show that the expansion of this haplogroup in northeast India occurred more than five thousand years ago."A serial decrease in expansion time from east to west: 5.7±0.3 Kya in Laos, 5.2±0.6 in Northeast India, and 4.3±0.2 in EastIndia, suggested a late Neolithic east to west spread of the lineage O2a1-M95 from Laos." Some linguistic models indicate that the Austroasiatic peoples likely reached the region bringing with it an aquatic culture. Historians too have noted that dry rice cultivation reached Assam from Southeast Asia."Rice was brought to Assam by neolithic horticultural people who spread out in all directions from their southeast Asian habitats... But they used to grow only the dry variety of it in their jhum plots..." Though some authors have suggested that the Brahmaputra valley may have been a center of dispersal of the Austroasiatic languages,"(T)here is a growing body of opinion that the center of dispersal of the Austroasiatic languages may have been in, or at least included, the Brahmaputra Valley (van Driem 2001: 289–94, Diffloth 2005)." this has been refuted by others."Such ["the area around the northern shores of the Bay of Bengal as the most likely location for the Urheimat of the ancient Austroasiatics.” (van Driem 2001:290)] considerations regarding the center of diversity and proto-lexicon, are subject to strong challenge (e.g. Sidwell and Blench 2011, Blench 2014) and now run against the current trend in discussions among concerned scholars in the Austroasiatic studies community."

They are expected to have settled in the foothills bordering the Brahmaputra Valley, to be either absorbed or pushed to the hills by subsequent migrants."They had perhaps earlier lived in the foothills bordering the Brahmaputra valley and were driven to the hills of the Meghalaya subsequently by the later migrants of the Tibeto-Burman stock." The Austroasiatic remnant today are represented by the Khasi and Pnar peoples in neighbouring Meghalaya; and who are also present in Assam's Karbi Anglong and Dima Hasao districts that adjoin Meghalaya,"The early Austro-Asiatics are now represented by the Mon-Khmer speaking Khasis (Syntengs and Pnars taken together) some of whom live in Karbi Anglong and North Cachar Hills districts of Assam adjoining Meghalaya." and who have traditions placing them in the Brahmaputra valley."The tradition indicates that there existed important kingdoms at the time the people had inhabited the Assam valley...(t)he ancient kingdoms known to us were Ka Meikha (Kamakhya), Muksiar, Mahadem, Mangkathiang and Malngiang." It is significant that in the context of the discontinuity in mtDNA in south asian and southeast asian populations the Khasi people have an equal admixture (40% S Asian and 39% SE Asian) of south/east Asian mtDNA as opposed to the Munda peoples (the Austroasiatic speakers in eastern India) who have predominantly south Asian mtDNA (75% S Asian and 0% SE Asian)."Notably, Khasi (the only Khasi-Aslian group of mainland India) speakers residing in Meghalaya state in India show an admixed package of both Indian and East Asian mtDNA haplogroups (fig. 2 and table 2)."

suggests that the Garo, Rabha, and some Koch peoples carry linguistic and social traces of past Austroasiatic peoples."The Garo, the Rabha and at least some of the Koch are, like the Khasi, matrilineal and uxorilocal. These features are not attested elsewhere in populations speaking Tibeto-Burman languages. These cultural features are best explained either by the deep and long influence of Khasi people on those Garo, Rabha, and Koch (all people now living around Meghalaya), or by the event of language shift, if we suppose that at least some of these people had Khasi ancestors. They would have abandoned their earlier Mon-Khmer languages because of the influential new TibetoBurman-speaking neighbours, but would have retained some important features of their social organization." "The mix [of Austroasiatic and Tibeto-Burman] would explain the group of Western Boro-Garo languages, deprived of diphthongs but equipped with specific consonant clusters (which interestingly are common in the Khasi languages) and Mon-Khmer-type social customs."

Tibeto-Burman