Sivasagar previously spelled Sibsagar (“the ocean of Lord Shiva”), is a town in Upper Assam, about 360 kilometres (224 mi) north east of Guwahati. It is the district headquarters of the Sivasagar district.

The main industries in Sivasagar are oil industry,tea industry & tourism industry. Majority of the population are agrarian.

It is well known for its Ahom palaces and monuments. Sivasagar today is also an important centre for the tea and oil industries.

Sivasagar, formerly known as Rangpur, was the capital of the Ahom Kingdom from 1699 to 1788. The Ahoms ruled Assam for six centuries, until their kingdom fell to the Burmese in 1819 and their ruling class was all but wiped out.

The province was liberated by the British in 1825 but, owing to the state of anarchy which prevailed, it was completely annexed in 1826. For administrative purposes it was divided into three sub-divisions.

It is said that the original name of Sivasagar was – ‘Kalansupar’ after the name of ‘Kalansu Gohain’ who resided in a village originally existed in the place where currently the Sivasagar tank is located.

This town’s main feature is the water body from which it takes its name. This is a 257-acre (1.04 km2) tank, also known as the Borpukhuri, which is at a higher elevation than the rest of the town, with three temples (“Dol”s in Assamese) on its banks. Of these temples, the most prominent is the Sivadol, standing tall at 104 feet (32 m), drawing large crowds on Shiv Ratri. The other temples are the Vishnudol and Devidol. The temples were built by Kuwori Ambika, wife of Swargadeo Siba Singha, in 1734.

Sivasagar is well connected by road with the rest of the state. State-run buses connect it to Guwahati, Dibrugarh, and Jorhat from the Assam State Transport Corporation’s (ASTC) bus station in Sivasagar. Private buses are also available. Taxis are also available for hire.

Auto-rickshaws and other modes of transport are available in and around the town. Cheaper modes of transport, like Tata Magic and Tempos, are available through Nazira, Mechagarh, and Joysagar to Sivasagar.

The closest airport is Jorhat Airport located at Jorhat, 75 km away from Sivasagar. The airport is connected, via regular flights, to cities like Guwahati, Kolkata, Bangalore, and Delhi. Sivasagar is also connected to Dibrugarh and Shillong. Another option for getting here is via Dibrugarh Airport, located at a distance of 95 km from the city. There are frequent flight services to both Jorhat and Dibrugarh. Taxis to Sivasagar are available from either airport.

The Dibrugarh-Bangalore Express connects through Sibsagar Town railway station. The nearest railway station on the Tinsukia-Guwahati sector of the North East Frontier Railways is located at Simaluguri, 16 kilometres (9.9 mi) from Sivasagar. Buses ply regularly from Simaluguri towards Sivasagar. It is approximately a half-hour bus ride from Simaluguri town.

The Assam State Electricity Board (A.S.E.B) Maibella is located to the east of Sivasagar. It has recently been renamed to Assam Power Generation Corporation Limited (APGCL).