 Located in the south of the eponymous oblast, the city proper lies on the Angara River, a tributary of the Yenisei, about 850 kilometres (530 mi) to the south-east of Krasnoyarsk and about 520 kilometres (320 mi) north of Ulaanbaatar.The Trans-Siberian Highway (Federal M53 and M55 Highways) and Trans-Siberian Railway connect Irkutsk to other regions in Russia and Mongolia.Many distinguished Russians were sent into exile in Irkutsk for their part in the Decembrist revolt of 1825, and the city became an exile-post for the rest of the century.