Omsk Oblast (Russian: О́мская о́бласть, Omskaya oblast) is a federal subject of Russia (an oblast), located in southwestern Siberia. The oblast has an area of 139,700 square kilometers (53,900 sq mi). Its population is 1,977,665 (2010 Census) with the majority, 1.15 million, living in Omsk, the administrative center.The oblast borders with Tyumen Oblast in the north and west, Novosibirsk and Tomsk Oblasts in the east, and with Kazakhstan in the south.