Bongaigaon district (Prpn:ˈbɒŋgaɪˌgãʊ) is an administrative district in the state of Assam in northeastern India. The district headquarters are located at Bongaigaon. The district occupies an area of 1,093 km2.

The Dooars or Duars are the alluvial floodplains in eastern-northeastern India and southern Bhutan that lie south of the outer foothills of the Himalayas and north of the Brahmaputra River basin. This region is about 30 km (19 mi) wide and stretches over about 350 km (220 mi) from the Teesta River in West Bengal to the Dhansiri River in Udalguri district of Assam. The region forms the gateway to Bhutan. It is part of the Terai-Duar savanna and grasslands ecoregion.