On December 1, 1965 the erstwhile North-East Frontier Agency was divided into five districts:
The districts of Arunachal Pradesh state are administrative geographical units, each headed by a deputy commissioner, an officer belonging to the Indian Administrative Service and a superintendent of police, an officer belonging to the Indian Police Service.
As of 2016, Arunachal Pradesh comprises 20 districts. Most of them are inhabited by various tribal groups. These are: