The name of Tinsukia is derived from the name 'Tinikonia' which means triangular. In fact, there exists one triangular tank (pukhuri) at Tinsukia, and the triangular is called as 'Tinsukia' in Assamese. Earlier it was the kingdom of Motok Raja Sarbananda Singh and it was a village called 'Bangmara'.  With the establishment of several tea-gardens and development of coal-mining etc. at Margherita, a Railway line was laid which was called as Dibru-Sadiya Railway and was owned by a British Company called Assam Railways & Trading Co. Ltd. The Railway line passed through this township and rail station was near this historical pukhuri called as Tinikonia Pukhuri and accordingly the Railway Station was named as TINSUKIA or TINISUKIA.  This is the event of 1904 or 1905.  Thereafter this township being surrounded by several teagardens and  started to grow.  By the discovery of Oil and establishment of 1^st Oil Refinery of the country at Digboi the growth of Tinsukia Town also picked up a speed.  The 1^st tea garden of Assam is “Chabua” which is also not far away from Tinsukia.   The biggest tea gardens like “Powai” now owned by Tata is also in the present Tinsukia district.

            The township of Tinsukia was earlier a  part of 'Lakhimpur' District having district Headquarter at Dibrugarh.  After bifurcation of 'Lakhimpur' district, two districts were made.  1^st North Lakhimpur and 2^nd Dibrugarh.  Then Tinsukia came under Dibrugarh district and later on in the year 1973 Tinsukia was made Sub-Divisional Headquarter under Dibrugarh District.

            In the year 1989 Tinsukia was declared a separate District with three Sub-Divisions, i.e. Tinsukia, Margherita and Sadiya which is the present political position.

            Before 1976 all the Judicial Courts were functioning at Dibrugarh, though Tinsukia was declared a Sub-Division in the year 1973.

            In December, 1975 the Judicial history of Tinsukia started with the establishment of two Courts i.e. (i) the Court of the SDJM and (ii) the Court of the Munsiff.  The 1^st SDJM was Sri B.N. Sharma (who retired as District Judge) and the 1^st Munsiff was Mr. M.M. Sarkar (who also retired as District Judge)

            Since the workload of the Courts at Tinsukia was heavy and on the representation of the Bar Association of Tinsukia as well as of the  general public, the Court of the Asstt. District & Sessions Judge was established at Tinsukia  in the year 1986 and Sri P.K. Thakur was 1^st Asstt. District & Sessions Judge.  In the mean time two more judicial courts (one of 1^st Class and another of Judicial Magistrate) were also established. 

            Tinsukia was declared an independent district in the year 1989. But the Court of District & Sessions Judge was established in the year 1992 and the 1^st District & Sessions Judge was Mr. P N. Sharma.

            The Court of the CJM was established in the year 1990 and the 1^st CJM was Mr. B.C. Medhi.

            In the year 2000-2001 two Fast Track Courts were established and the 1^st Presiding Officers were Mrs. Jwahira Begum, who later on became the first lady District & Sessions Judge and Mrs. Dr. Indira Shah (now elevated as Judge of the Hon’ble Gauhati High court).

            The personalities like Mr. B.D. Agarwal has also served at Tinsukia Court as District & Sessions Judge and who is now functioning as the Judge of Hon’ble Gauhati High court.  Tinsukia is also the birth place of Mr. Safiqul Haque, who was the Acting Chief Justice of Gauhati High court.  At present strength of Judiciary at Tinsukia is in double digit i.e. (1) District & Sessions Judge, (2) Two Fast Track Courts, (3) Asstt. District & Sessions Judge, (4) CJM, (5) Addl.CJM, (6) SDJM, (7) Two Munsiffs, (8) 2^nd Class Judicial Magistrate and (9) Special Railway Magistrate