During the pre-British rule the territory of the present district was part of the Dimasa Kingdom till the demise of Sengya Tularam Hasnu in AD 1854. It was during his time that Diphu(which means white river in Dimasa)present headquarter of district became a prominent town. After his death the territory went into the hands of the British under which it was declared a ‘Scheduled District’ constituted in 1874. Later, Mikir Hills tract was constituted as “Partially Excluded areas” under the Govt. of India Act, 1935. On November 17, 1951 a new district, the United Mikir Hills and North Cachar Hills district was created by combining some parts of the districts of Sibsagar (now Golaghat), Nagaon, Cachar and United Khasi and Jayantia Hills district of present day Meghalaya state. This was followed by bifurcation of the erstwhile district of United Mikir and North Cachar Hills district into two separate districts — Mikir Hills district and North Cachar Hills district — on 2 February 1970. Mikir Hills district was renamed as Karbi Anglong district on 14 October 1976
