Irkutsk is situated in a landscape of rolling hills within the thick taiga that is typical in Eastern Siberia. According to the regional plan, Irkutsk city will be combined with its neighboring industrial towns of Shelekhov and Angarsk to form a metropolitan area with a total population of over a million.Irkutsk originally had a borderline subarctic climate (Köppen climate classification Dwc).
The ostrog gained official town rights from the government in 1686.
Trans-Siberian Highway (Federal M53 and M55 Highways) and Trans-Siberian Railway connect Irkutsk to other regions in Russia and Mongolia.
Irkutsk was named after the Irkut River, whose name was derived from the Buryat word for "spinning" and was used as an ethnonym among local tribes as Yrkhu, Irkit, Irgit, and Irgyt.
In 1821, as part of the Mikhail Speransky's reforms, Siberia was administratively divided at the Yenisei River and Irkutsk became the seat of the Governor-General of East Siberia.
In the early 19th century, many Russian artists, officers, and nobles were sent into exile in Siberia for their part in the Decembrist revolt against Tsar Nicholas I.
The city subsequently became the administrative center of Irkutsk Oblast after East Siberian Oblast was divided into Chita Oblast and Irkutsk Oblast.