Digboi is a town and a town area committee in Tinsukia district in the north-eastern part of the state of Assam, India.
Crude oil was discovered here in late 19th century. Digboi is known as the Oil City of Assam where the first oil well in Asia was drilled.
The first refinery was started here as early as 1901. Digboi has the oldest oil well in operation. The Digboi Refinery modernization project was taken up in large scale in order to overcome the technological obsolescence of the old refinery.
Subsequently a number of other major projects were undertaken by Assam Oil Division to further revamp and modernize Digboi Refinery.
Digboi refinery has been awarded the ISO-14001 and OHSMC certificate.