There are about 20 major tribes in Arunachal Pradesh. Most of them are either of the Tibetan or of the Thai-Burmese stock. As their dates of migration from their original homelands vary, each tribe have developed their colourful culture significantly different from other tribes, including their language and the faith they follow. Tibetan Lamaism, Animism, Hinduism and Theravada Buddhism are the main faiths that were followed by the Arunachalis. They are further sub-divided into many standard tribes and sub-tribes. In this list, the tribes are classified by the faith that they embrace.
ArunachalPradesh, bordered on the south by Assam state, on the west by Bhutan, on the north and northeast by China, and on the east by Myanmar (formerly known as Burma) is a sparsely populated mountainous area in the extreme northeastern part of the subcontinent.
The state's main rivers are the Brahmaputra known in ArunachalPradesh as the Siang, and its tributaries, the Tirap, the Lohit (Zayü Qu), the Subansiri, and the Bhareli.
In western ArunachalPradesh the main tribes are the Nissi (Nishi or Dafla), Sulung, Sherdukpen, Aka, Monpa, Apa Tani, and Hill Miri.