Siberia (/saɪˈbɪəriə/ sy-BEER-ee-ə; Russian: Сибирь, romanized: Sibir', IPA: [sʲɪˈbʲirʲ] ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states since the lengthy conquest of Siberia, which began with the fall of the Khanate of Sibir in 1582 and concluded with the annexation of Chukotka in 1778. Siberia is vast and sparsely populat