Tinsukia is located in the upper part of Assam and is surrounded by Arunachal Pradesh in the south-east, Dibrugarh district in the south-west and Dhemaji district in the north. Tinsukia has a geographical area of 3790 sq. km. It was declared as the 23rd district of Assam on 1st October 1989 with three sub divisions Tinsukia, Margherita(M) and Sadiya.
The ancient name of Tinsukia was Bangmara which was orginally known as Changmai Pathar. It was the capital of the Muttack Kingdom. The Bangmara city was built by King Sarbananda Singha with the help of his Minister Gopinath Barbaruah alies Godha who dug a triangular shaped pond in Bangmara known as "Tinikunia Pukhuri". In 1884 Dibru-Sadiya Rail line was constructed and a station was set up near the "Tinikunia Phukhuri" which was named as Tinsukia. Since then the city has been known as Tinsukia.