History of Tirap district includes a number of administrative developments that resulted in the formation of this district. The beginning of the administration of Arunachal Pradesh is traced back to the Scheduled Districts Act of 1874 of the Government of India. This act provided a schedule of districts where the Local government could decide as to which of the enactments of the Government of British India are in force and which are excluded. As a result, several Hill Tracts (territories) were placed under the Chief Commissionership of the state of Assam as local government. Following this, again in the year 1880, Assam Frontier Tracts Regulation was passed that provided for removal of certain frontier tracts in Assam inhabited or frequented by semi-civilized tribes from the operation of enactments of British Government to be in force. This power was vested in the Chief Commissioner of Assam.

In the year 1914, the notifications of the Government of India, Foreign and Political Department, it was mentioned that the Assam Frontier Tracts Regulation of 1880 would extend to the hills inhabited by the Abors, Miris, Mishmi tribe, Singhpho tribe, Naga tribe, Khamti tribe, Bhutias, Aka tribes and Nishing tribe. It meant that the Chief Commissioner of Assam was hereafter free to leave out any of these areas from any of the enactments of the government and also employ officers for smooth administration of the region. These notifications also approved boundaries of two units which would henceforth consist of the North-East Frontier Tract.

These were named as -

•The central and eastern section, North East Frontier Tract
•The Western Section, North East Frontier Tract

The Indian Penal Code was extended to both sections in the year 1916. The Central and Eastern Section had its headquarters at Sadiya. In the year 1919, this section was renamed as `Sadiya Frontier Tract.` In the year 1937, these two tracts, along with the Lakhimpur Frontier Tract of Assam came to be jointly known as `Excluded Areas of province of Assam` under the provisions of Government of India Act, 1935. It specified that the legislative or administrative control of the regional Government of Assam was excluded from these areas. Thus, the actual administration of the Frontier Tracts was hence carried out by the Governor of Assam. The secretariat was formed in the year 1937 and the expenses were borne by the state government.

Further, the history of Tirap district makes it clearly evident that the occupation of tribal territories all over India was marked by a series of disciplinary measures by the British Government. In the year 1943, these areas were brought under standard administration through gradual penetration of organizational machinery. Consequently, the post of Adviser to the Governor of Assam was accordingly formed in the year 1943. Under the International Administration Regulation 1943 of the North Eastern Frontier Tract, a new administrative unit was created by merging certain areas of the Sadiya and the Lakhimpur Frontier Tracts and was named as Tirap Frontier Tract. It was placed under a separate political officer with its headquarters at Margherita in Assam.

After the independence of the country in 1947, the Governor was divested from of his discretionary powers in respect of the North-East Frontier Tracts and subsequently the administrative control was passed on to the Government of Assam by provisions of the Indian Independence Act of 1947. This arrangement continued till the year 1950 when the Government of Assam was reassured of its responsibility of administration of North-East Frontier Agency and the discretionary power was re-invested in the Governor of Assam. Further, in 1951, the plains portions of Tirap Frontier Tract were transferred to the administrative jurisdiction of Government of Assam. The remaining hill areas of the frontier tracts were cooperatively renamed as North-East Frontier Agency. Under the regulation of 1954, Tirap Frontier Tract was renamed as Tirap Frontier Division with its headquarters at Khela that was later shifted to Khonsa in the year 1956. Again, in 1965, the Frontier Division was renamed as Tirap District and the classification of Political Officer was changed to that of Deputy Commissioner under the North East Frontier Agency (Administration) Regulation of 1965.

The history of Tirap district also suggests that in the year 1987, this district was divided into two districts - Tirap and Changlang district with its headquarters at Khonsa. The name of Tirap district was derived from river Tirap.