Until the early 16th century, the land within the Sibsagar district was part of three kingdoms viz.
Ahom kingdom,
Chutia kingdom and
Kachari kingdom. The Burhi-Dihing river which once flowed through the central region of Sibsagar formed the borders between Ahom and Chutia territories, while Dikhou on the southern region demarcated Kachari and Ahom territories. In early 16th century, Ahoms under the reign of Suhungmung defeated Chutia first and Kachari later to annex the entire district. Before the British period, the center of administration of Assam was around Sivasagar were the famous
Ahoms ruled for nearly six hundred years. The Ahom kings took keen interest in building different temples, dedicated to various deities and which were usually flanked by large tanks which until today stand out as memorials to their glory in the district. The original name of Sivasagar district was Sibpur. On February 24, 1826, the treaty of Yandaboo consolidated the British occupation of Assam. This
treaty of Yandaboo brought an end to the roughly six hundred year long Ahom rule in Assam. After the 1826 treaty, the British government in Assam incorporated a number of administrative changes such as the formation of districts. The Sivasagar district was created after the annexation of
Purandar Singha's dominion of upper Assam in 1839. The Sadar headquarter of Sivasagar was transferred to Jorhat in 1912–13. The undivided old Sivasagar district comprised three subdivisions, namely Sivasagar, Jorhat and Golaghat. In 1983, the Sivasagar district was reorganized to carve out the
Jorhat district. It was further divided on 15 August 1987 for the creation of the
Golaghat district. ==Geography==