The oblast of Irkoutsk (in Russian: Ирку́тскаяо́бласть) is a federal subject of Russia (Oblast), located in the south-west of the Siberia, in the Bassin S of the rivers Angara, Lena and Nijnaïa Toungouska, and covers a surface of 767  900 km ², which represents 4,6  % of the total surface area of Russia. With the census of 2002: 2581705 people lived the oblast, whose administrative center is Irkoutsk.