Tripura a hilly, picturesque, princely state was first conquered by the Britishers in 1761. However, no political agent was appointed till 1871 and the Maharaja ruled hill territory " Hill Tipperah " almost independently.
The State acceded to the Indian union on 13.08.1947, the agreement of merger being signed on 09.09.1949. The administration was formally taken over on 15.10.1949.Tripura, initially a one district state, was trifurcated into three Districts w.e.f. 01.09.1970. The North Tripura District started functioning in the office of the Sub-divisional officer at Kailashahar and partly at Kumarghat, later the whole office was shifted to Kailashahar. The Collectorate was shifted to the newly constructed complex at Gournagar on 13.11.1987.
Subsequently, North Tripura District has been bifurcated and a new District namely "Dhalai District" has been inaugurated on 14.04.1995 with district head quarter at Ambassa.
On 21.01.2012 the decision to further bifurcate North Tripura District was accepted and the district "UNAKOTI DISTRICT" was created with its headquarter at Kailashahar.