In 1914, some tribal-majority areas were separated from the former Darrang and Lakhimpur districts of Assam Province of British India to form the North-East Frontier Tract (NEFT).
This proved to be a landmark step in the history of NEFA which later emerged as the state of Arunachal Pradesh.
In 1946, Balipara Frontier Tract was divided into two administrative units: Sela Sub-Agency and Subansiri Area.
[1][non-primary source needed] After the independence of India in 1947, NEFT became a part of the Assam state.
On 21 January 1972, the North-East Frontier Agency became the Union Territory of Arunachal Pradesh and was placed under the charge of a Chief Commissioner.