[3] Under the Mughals, it was constituted as Sarkar Dhekuri,[4] and it passed into East India Company control along with Bengal in 1765 and it fell under the Rangpur administration.
As a part of the East India Company's frontier policy a special administrative region, called "North-Eastern Parts of Rangpur", was constituted sometime after 1816, with David David Scott appointed as its Civil Commissioner in January 1822.
[6] Within the first month of the First Anglo-Burmese War (March 1824), the regions to the east of Rangpur, Kamrup and Darrang (under the erstwhile Ahom kingdom, then under Burmese occupation).
[7] By October 1824, the newly acquired region came under administrative control of David Scott, the Chief Commissioner of "North-Eastern Parts of Rangpur"[8] and the historical grouping of the Goalpara, Kamrup and Darrang (largely congruous to the erstwhile Koch Hajo) called Western Assam (later Lower Assam) became apparent.
[9] The Burmese abandoned the Ahom capital Rangpur, Assam in 1825 and following the Treaty of Yandabo of February 1826, the whole of the Ahom kingdom, except the Sadiya and the Bengmara i.e the areas under Matak kingdom (1805–1839), fell under direct British control and came to be called Eastern Assam.