|Area||83,743 sq km|
|Principal Languages||Monpa, Miji, Aka, Sherdukpen, Tagin, Hill Miri, Adi, Khamti, Nocte, Tangsa|
History and Geography: Arunchal Pradesh, the erstwhile North-East Frontier Agency shares international boundaries with Bhutan, Tibet, China and Myanmar to the west, north-east, north and east respectively, and the 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 the rivers Kameng, Subansiri, Siang, Lohit and Tirap.
There are practically no records relating to the history of this area, except some oral literautre and a number of historical ruins found mainly in the foothills. Subsequent explorations and excavations have identified the ruins as dating approximately from the early Christian era. The historical evidence indicates that not only was the area well known, but the people living here had close relations with the rest of the country.
Modern history of Arunachal Pradesh, begins with the inception of British rule in Assam after the treaty of Yandaboo concluded on 24 Feburary 1826. Before 1962 the area was populary 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 the Ministry of External Affairs until 1965 and subsequently by the Ministry of Home Affairs, through the Governor of Assam. In 1972 it was consistuted as a Union Territory and renamed Arunachal Pradesh. On 20 February 1987, it became the 24th state of the Indian Union.