Presently, the Union Territory of Andaman and Nicobar Islands comprises 3 districts:
History
On 1 August 1974 Nicobar district was separated from Andaman district. On 18 August 2006, Andaman district was bifurcated into two districts: North and Middle Andaman district and South Andaman district.
References
List of districts of the Andaman and Nicobar Islands Wikipedia(Text) CC BY-SA