Assam is acknowledged as the settling land for a lot of cultures. A number of tribal grouping have landed in the soils of Assam in the course of diverse directions as the territory was linked to a number of states and many different countries. Australoids, Mongoloids, and Indo-Aryans had been the most important traditional groups that arrived at the site and lived in the very old Assam. They were well thought-out as the ‘aborigines’ of Assam and yet at the moment they are essential elements of the “Assamese Diaspora”.
The Assamese people are a physically diverse group formed after years of assimilation of Austroasiatic, Dravidian, Indo-Aryan, Tibeto-Burman and Tai races. The total population of native Assamese speakers in Assam is nearly 13 million which makes up 48.8% of the Assam's population according to the Language census of 2001. Though there is a political dispute over the definition of Assamese people in Assam, in general; the people belonging to the state of Assam along with belonging to an indigenous community of Assam and speaking the Assamese language or any tribal dialect of Assam as his/her first language are referred as Assamese people.
The indigenous Assamese people traditionally include ethnic groups like Assamese Brahmins (including Ganaks), Koch Rajbongshis, Ahoms, Deoris, Sonowal–Kacharis, Rabhas, Hajongs, Mishings, Assamese Kayasthas, Chutias, Kalitas, Keot(Kaibarta), Baro-Bhuyan, Mech Kacharis, Thengal–Kacharis, Tiwas, Sarania Kacharis, Nath, Kumar, Hira, Tai-Phake, Tai-Aiton, Tai-Khamyangs, Tai-Khamti, Tai-Turung, other Tai groups, Moran, Motok, Doms/Nadiyals, Assamese Muslims (particularly Goria, Moria, Deshi communities), Assamese Sikhs, Assamese Christians speaking Assamese or any other tribal dialect of Assam as their mother tongue and indigenous ethnic groups of other neighbouring North-East states.
The Greater Kachari Tribe (কছাৰী) encompasses the 18 major tribes of Assam, both plain and hills, viz., Bodo, Dimasa, Sonowal, Mech, Tiwa, Garo, Rabha, Sarania, Hajong, Tripuri, Deori, Thengal, Hojai, Koch and others. The greater Kachari tribe can also be referred as the Bodo-Kachari but it should not be confused that all Kacharis are Bodo (বড়ো, pronounced 'Bo-rho'); Bodo is one of the major tribes amongst the Kachari. The ancient land of 'Kirat' is also referred to the land of the Kachari.
Bodo Kacharis were historically the dominant group of Assam, who were later dominated in the 1500s by the Tai Ahoms, the ethnic group who along with the Upper Assam Bodo-Kachari groups like Morans and Borahis were associated with the term "Assamese". Along with Tai Ahoms, they were other prominent groups that ruled Assam valley during the medieval period, those belonging to the Koch, Chutiya, and Dimasa Kachari communities. The first group ruled Lower Assam from 1515 to 1949, the second group from 1187 to 1673 in the eastern part of the state, while the third group ruled southern part of Assam from the 13th century to 1854. Bodos are the dominant group in BTAD. They speak the Bodo language among themselves along with using Assamese to communicate with other indigenous Assamese communities as the lingua-franca.
Most of the indigenous Assamese communities today have actually been historically tribal and even the now considered non-tribal population of Assam were actually tribes which have slowly been converted into castes through Sanskritisation. Actually, more than 70-75% or more of the now considered non-tribal population of Assam actually have Mongoloid roots and origin and thus were historically tribal. Some of the tribal groups were able to enter into the Hindu upper caste society while some of them remained in the tribal or lower caste society. Thus, Assam has always been a historically tribal state.
Ahoms along with Chutiya, Moran, Motok, Keot(Kaibarta) and Koch are still regarded as semi-tribal groups who have nominally converted to Hinduism even though keeping alive their own tribal traditions and customs. Various indigenous Assamese communities in Assam like Koch-Rajbongshi, Keot (Kaibarta), Kachari, Chutiya, Moran, Motok, Ahoms etc (all having tribal origin) have slowly been converted into a caste through Sanskritisation.
The Karbis mentioned as the Mikir in the Constitution Order of the Government of India, are one of the major indigenous ethnic tribe in Northeast India and especially in the hill areas of Assam. The great artist-scholar Bishnu Prasad Rabha refer to them as the Columbus of Assam. They prefer to call themselves Karbi, and sometimes Arleng (literally "man" in the Karbi language). The term Mikir is now considered derogatory. The closest meaning of Mikir could be said to be derived from "Mekar". The Karbis are the principal indigenous tribal community in the Karbi Anglong district of Assam, a district administered as per the provisions of the Sixth Schedule of the Constitution of India, having an autonomous district of their own since 17 November 1951.
Besides Karbi Anglong district, the Karbi-inhabited areas include Dima Hasao, Kamrup, Morigaon, Nagaon, Golaghat, Karimganj, Lakhimpur, Sonitpur and Biswanath Chariali districts of Assam; Balijan circle of Papumpare district in Arunachal Pradesh, Jaintia Hills, Ri Bhoi and East Khasi Hills districts in Meghalaya, and Dimapur District in Nagaland. Apart from Assam, where the Hill Karbis are recognised as Scheduled Tribes but not the Plain Karbi, the Hill Karbis in Meghalaya, Mizoram and Nagaland as Mikir but they are not able to obtain ST certificates due to their current name as Karbi. With a population of around 4 lakhs 6 thousand (406,000) as per 2001 Census, the Karbis constitute a large community.
The Mising is an indigenous tribal community inhabiting 11 districts of Assam and Arunachal Pradesh. They were earlier called Miris in historical days. and the Constitution of India still refers to them as Miris. Miri is the older name and traces back to the ancestor Abo Tani. Misings are recognised as a Scheduled Tribe by the Indian government under the name 'Miri.' Mising derives from the two words Mi and Yasing. 'Mi' means 'men,' while 'yasing' means fair or worthy, so 'Mising' means a 'worthy man.' To depict other indigenous Assamese communities the word Mipak is used extensively. Mipak is the opposite meaning of Mising.
According to Census of India conducted in 2011, the population of Mising in Assam is 6,87,310; of which 3,95,790 are male and 2,67,520 female. They live in 10 districts of Assam: Dhemaji, Lakhimpur, Sonitpur, Tinsukia, Dibrugarh, Sivasagar, Majuli, Charaideo, Jorhat and Golaghat, and in three districts of Arunachal Pradesh: East Siang district, Lower Dibang Valley, and Lohit.
The Ahom are the descendants of the ethnic Tai people who accompanied a Tai prince, Sukaphaa, in his migration from what is now the frontier regions between Myanmar and Yunnan Province in southwest China into the Brahmaputra valley in 1228. Sukaphaa and his followers established the Ahom kingdom (1228–1826), which controlled the Brahmaputra Valley and the territory of modern Assam until the British gained control of the region through the Treaty of Yandabo after their 1826 victory in the First Anglo-Burmese War. In the early days of the Ahom kingdom, although the Ahom made up a relatively small portion of the kingdom's population, they maintained their original Tai language and practised their traditional religion. Over time, however, the kingdom adopted the dominant local language, Assamese, and the royal court eventually converted to the dominant local religion, Hinduism. The modern Ahom people and their culture are a syncretism of their original Tai culture and the cultures they interacted with in Assam. Some local ethnic groups, including the Tibeto-Burman speaking Borahi, were completely subsumed into the Ahom community, while members of other communities, based on their allegiance to the Ahom kingdom or the usefulness of their talents, were accepted as Ahom. Currently, they represent the largest Tai group in India, with a population of nearly 4 million in Assam, and are the majority ethnic group in the Upper Assam Division. The name "Ahom" is an exonym applied by local Tibeto-Burman groups to the Ahoms.