In India, the Northeastern region is quite charming and interesting enough to be known about. Among the eight Northeastern States, the modern history of Arunachal Pradesh, begins with the inception of British rule in Assam, after the treaty of Yandaboo concluded on 24 February 1826. Before 1962, the area was popularly known as the North East Frontier Agency (NEFA), and was constitutionally a part of Assam. Because of its strategic importance, however, it was administered by Ministry of External Affairs till 1965 and subsequently by Ministry of Home Affairs, through Governor of Assam. In 1972, it was constituted as a Union Territory and renamed Arunachal Pradesh. On 20 February 1987, it became a state of the Indian Union.
Arunachal Pradesh, the erstwhile North East Frontier Agency, shares international boundaries, with Bhutan, Tibet, China and Myanmar to west, northeast, north and east respectively, and state boundaries with Assam and Nagaland. The terrain consists of submontane and mountainous ranges, sloping down to the plains of Assam, divided into valleys by rivers Kameng, Subansiri, Siang, Lohit and Tirap. There are practically no records, relating to the history of this area, except some oral literature and a number of historical ruins, founds mainly in foothills. Subsequent explorations and excavations have identified the ruins, as approximately from early Christian era. The historical evidence indicates that not only was the area well known, but the people living there had close relations with the rest of the country, also.