Irkutsk (ĭrkōtskˈ) [key], city (1989 pop. 626,000), capital of Irkutsk region, S Siberian Russia, at the confluence of the Angara and Irkut rivers. It is an industrial center, a port, the site of a hydroelectric dam, and a major stop on the Trans-Siberian RR. Manufactures include aircraft, automobiles, machine tools, textiles, chemicals, food products, and metals. Founded as a Cossack fortress in 1654, Irkutsk became the capital of Eastern Siberia in 1822. It has been a place of exile since the 18th cent. Many of the Decembrists settled in Irkutsk after their imprisonment, and a few of their houses are now open as tourist sites. In the city are a university (founded 1918) and several agricultural, medical, and technical schools. The Irkutsk dam has raised the level of nearby Lake Baykal by 20 ft (6 m).