Except for the northwestern parts of the state, very little is known about the history of Arunachal Pradesh.

The northwestern parts were under the control of Monpa kingdom of Monyul, which flourished between 500 B.C. and 600 A.D. Subsequently the region came under the loose control of Tibet and Bhutan, especially in the Northern areas. The region then moved to the hands of Ahom and the Assamese until the annexation of India by the British in 1858.

After India got her independence in 1947, the region was known by the name of North Eastern Frontier Agency (NEFA) and was constitutionally a part of Assam.

It was administered by the Ministry of External Affairs until 1965 and subsequently by the Ministry of Home Affairs through the Governor of Assam.

On 21 June, 1972, it was conferred the status of a Union Territory and renamed Arunachal Pradesh. On 20th February, 1987, it got the status of a state and became the 25th state of the Indian Union.