The total population of the district is 9,06,315 nos. as per 2001 Census. The northern part of the district is predominantly inhabitated by Bodos, Central part by Assamese Koch Rajbongshis, Assamese caste Hindus and Scheduled castes, the south eastern part by immigrant Muslims and south western part by mixed population including indigenous Muslims.


The block-wise dominant population pattern is shown below:

SIDLI-CHIRANG DEVELOPMENT BLOCK : Bodos and Assamese Rajbongshis. There are about 60 Bihari families at Garubhasa beside few hundred Adivasis and Nepalis.
BORO BAZAR DEVELOPMENT BLOCK : Predominantly Bodos and Assamese Rajbongshis and S.C.
DANGTOL DEVELOPMENT BLOCK  : Assamese Rajbongshis and Assamese Caste Hindus beside a couple of thousands of Biharis and few hundred others in and around railway colonies.
MANIKPUR DEVELOPMENT BLOCK : Assamese Rajbongshis and Assamese caste Hindus and indigenous Muslims.
BOITAMARI DEVOLEPMENT BLOCK : Assamese Rajbongshis, Assamese   Caste Hindus beside few thousand of Assamese S. C. and Garos.
SRIJANGRAM DEVELOPMENT BLOCK : Assamese Rajbongshis, Assamese Caste Hindus and indigenous Muslims.
TAPATTARI DEVELOPMENT BLOCK : Indigenous and immigrant Muslims beside few hundred Biharis.

There are 3 nos. of urban areas namely Bongaigaon town, Bijni town and Abhayapuri town. The total urban population is estimated to be about 1.20 lakhs at present out of which the number of Biharis is about 15,000 and Marwaris about 12,000. The concentration of Biharis and Marwaris are comparatively higher at Bongaigaon town. Beside it, Hindu Bengalis constitute a major fraction at Bongaigaon and Bijni town.

The Marwaris are mainly concentrated in urban areas or in semi urban areas. But the Biharis are residing in some pockets in rural areas also in midst of Assamese speaking peoples. Such pockets have been identified.