Historically, the bodoland territorial region has been inhabited by the Boros or Bodos or Kacharis and Mechs. During the reign of the king of Kamata Nara Narayan, the country was inhabited at the foot of the hills of Bhutan, i.e. the Eastern and Western Dooares, by the Bodo or Mech tribe.  These areas are known as Kachari Duar and Mech Duar. The British took control of the area, from the Sankosh River in the west to the eastern border of colonial Assam. while the western part (Dooars) remained under British rule as Darjeeling and part of Nepal. Thus these present-day regions of Bodoland were finally ruled by King Bara. Treaty of Yandabo after the victory of the first Anglo-Burmese War in 1826. The war was mainly for control of Northeast India between the British and Burmese empires. It was known as the Kachari Dwars or kachari plains or kachari country by the British during the British Raj. The Bodo of the Brahmaputra Valley survived the invaders and settlers in the middle of Khilji, Mughal, Aryan and Shan. Mech-Bara Descent Bara kings ruled different parts of Lower Assam and North Bengal. Open caste leader became a semi-Hindu Aboriginal caste, left the traditional culture and began to adopt Aryan culture, although it did not fully adopt Aryan culture as they still worship asurs (non-Aryan ancestry) and other traditional gods.
The surviving remains of the Bara Empire royal family turned out to be Aboriginal members of the Mech caste and spoke Tibeto-burman. After the separate state movement of Bodoland, these tribal areas are called Bodoland. This agreement can be called the Bodoland Territorial Region or BTR Accord, since the existing Bodoland Territorial Areas District or BTAD has been renamed BTR. The BTR agreement is unique in that it is the first peace agreement in the northeast, in which all insurgent groups in a given region have signed their signatures with a common commitment to end the violence and seek progress and development. A masterpiece of government negotiators is their flexible approach of seeing the region`s student organization, ABSU, as a signatory to the agreement. Bodoland (also Boroland), officially the Bodoland Territorial Region, is an autonomous region of Lower Assam, in northeastern India. It consists of four districts on the north bank of the Brahmaputra River, in the foothills of Bhutan and Arunachal Pradesh. It is managed by an elected body, known as the Bodoland Territorial Council and concluded as part of a peace agreement signed in February 2003, and its autonomy was renewed by an agreement signed in January 2020.
The area covers more than 8,000 square kilometres and is mainly inhabited by the Bodo and other indigenous communities in Assam.   2003: A second tripartite bodo agreement was signed between the central government, the Assam government and the militant group Bodo Liberation Tigers (BLT). As a result of this agreement, the Bodoland Territorial Council (BTC) was established in Assam as part of the sixth calendar of the Constitution. The areas under the BTC jurisdiction are known as the Bodoland Territorial District (BTAD) and include four districts bordering Udalguri, Baska, Chirang and Kokrajhar. 3.1. The territory of the proposed BTC covers all 3082 villages and territories that must be notified by the government. The villages and areas mentioned above, following the restructuring of the existing districts of Assam, will be divided into 4 coherent districts within six months of the signing of the agreement, modelled on the BLT proposal, subject to the approval of the delimitation commission.