The name of district is derived from the river Lohit that flows through the district. Prior to 1914, the district was a part of Lakhimpur district. By 1914 the North East Frontier Tract was constituted with three political charges and the area covered by this district become a part of the central and Eastern Section which falls under one of the said political charges. In the year 1919, the Central and Eastern Section was renamed as the Sadiya Frontier Tract. In 1943, some area from both the Sadly Frontier Tract and the Lakhimpur Frontier Tract were curved out and Tirap Frontier Tract was formed. In 1948, under the North East Frontier Tracts (Internal Administration) Regulation, 1948, the remaining portion on the Sadiya Frontier Tract was divided into two separate administrative charges, namely the Abor Hills District and the Mishmi Hills District each in the charge of a political Officer with headquarters at Pasighat and Sadiya respectively.

In 1951, the plains portion of the Mishmi Hills District was transferred to administrative jurisdiction of the Government of Assam. In 1952, the headquarters of the Mishmi Hills District was shifted fro Sadiya to Tezu. According to the North East Frontier, areas (Administration) Regulation 1954, the North-East Frontier Tract came to be known as North-East Frontier Agency and the Mishmi Hills District was renamed as the Lohit Frontier Division. In 1956, the Dibang Valley was constituted as a separate administrative unit within the division and placed under the charge of Additional Political Officer with his headquarters at Roing which was subsequently shifted to Anini.

In 1965, under the North-East Frontier Agency (Administration) Regulation, 1956 the Lohit Frontier Division came to be known by its present name the Lohit District and the Political Officer and Additional Political Officer were redesignated as the Deputy Commissioner and Additional Deputy Commissioner respectively. In June, 1980 under the Arunachal Pradesh (Re-organisation of district), Act 1980 the Lohit District was bifurcated into two independent district namely Lohit District and Dibang Valley District. The District headquarters of the Lohit District is at Tezu.

The ancient history of the individual Lohit District is not concreated due to paucity of historical evidence, literary or material, yet the lower belt of the district is the base for evidence for existence of the ruins of ancient settlement, buildings, shrines and temples. The Parasuram Kund,Tamreswari temple,Sivalinga site and the city of king Bhismak situated in this region are also mentioned in the Puranic and tantric literatures.

The scenic beauties of the district are splendid, Tezu Township alone attracts visitors for its set up. There are different tribes in the district. Their traditional dances, games and sports can be enjoyed in festive occasion. Elephant raiding, angling, rafting, hitchhiking, mountaineering etc. are the entertainment scopes available in the district.