Buddhism in North-East India is not a new faith. It exists long ago playing its role in many forms according to the period concerned. Many scholars believe that Buddhism reached to North-eastern region of India around 16th -17th century, and also consider that it did not arrived at the time of the Buddha and even in the phase of the great Buddhist patronage king Asoka who send missionaries to different direction of Majjhimadesa and abroad. It is a matter of discussion and research.
There are three races exist in North-East India, Negrito, Proto-Australoid and Mongoloid. The Tribes of North-East are predominantly Mongoloid. The Mongoloid population entered the region of Assam through various routes at different times and they speak the languages classified broadly as Tibeto-Burman. The Ahom of the Tai or Shan group of the Mongoloids entered Assam in the 13th century conquering it, they mainly settled in the Upper Assam. They were followed by other Shan tribes like the Khamti, Khamyang, Aitong, Phakial and Turung – all are believers of Buddhism, occupying isolated pockets and preserving their traditional socio-cultural ways of life. Today, the Archaeological evidences of the Surya Pahar of Goalpara (in Assam- an archaeological Buddhist site) where Stupas, Terracotta plaques with figure of Buddha found in the excavation which indicate that Buddhism flourished in lower Brahmaputra valley during the early part of the Christian era back to the 9th Century A.D.
In Tripura 100 km from Agartala we have Pilak, a Buddhist site excavated by the Archaeological Survey of India in 1984-85, where many Hindu and Buddhist images were found. This also recorded by the expert dating back to the 9th century A. D., these sculptures are living proof of a historical past in this region. Today Pilak has become a major attraction of Buddhist site of pilgrimage.
In the Arunachal Pradesh there are 6 Tribes inhabiting in western, central and eastern region of it, out of 22 tribes namely Monpa, Sherdukpen, Memba, Khamba, Khamti and Singpho. Population wise Monpa is the largest among the 6 tribes and they are followers of Buddhism. The Arunachal Pradesh is one of the most Buddhist flourished state in the North-East region of India. However, in Arunachal Pradesh Buddhism can be termed as Tibetan form of Buddhism due to influence of Tibet to a great extent. But the tribes like the Khamti, the Singpho and the Tikahk Tangsa are still believer of Theravada form of Buddhism. As per the census of 2011, in Arunachal Pradesh, the total number of Buddhist population are 1,43,028, which is13.03% approximately of the total population of the state i.e., 10,97,968. These Buddhist tribes have contributed immensely to the art and culture of the state and their socio-cultural-religious life; monuments etc. are important components of Arunachal Pradesh. There are many significant Monasteries in that region such as Tawang Monastery, Bomdila Monastery and Urgelling Monastery. Tawang is known as the crown of Buddhism in Arunachal Pradesh, which is the core of the Tibetan faith of the Mahayana School of Buddhism in the region, making it the largest monastery in India and the second largest of Asia.
There are 19 groups of scheduled tribes in Tripura, S. T. Das (1986) tabulates the strength (1971) of main six schedule tribes are Tripuri, Reang, Chakma, Jamatia, Mag/Magh/Mog and Maring. Among them the Chakma and Mog are traditionally the followers of Theravada Buddhism.
Sikkim comprises of different ethnic communities broadly classified as the Lepcha, Bhutia, Nepali and the Indian Plainsmen. Among them Lepchas are major populations in the region who are follower of Buddhism. Though the Buddhist Population in the North-East India is in minority but its contribution is unique among the social and cultural activities among the people of this region. The life style of the Tribal people in North-East India is the result of the influence of Buddhism on the local people. Simplicity in dress and ornaments, socio-economic life all are part of Buddhism though most of the tribal and non-tribal people may not be direct followers of the faith but are influenced by the teachings of the Buddha as are reflected by their lifestyle.