Dzungaria (also spelled Zungharia) is a geographical region in northwest China corresponding to the northern half of Xinjiang, also known as Beijiang (Chinese: 北疆; pinyin: Běijiāng; literally: "Northern Xinjiang"). Bounded by the Tian Shan mountain range to the south and the Altai Mountains to the north, it covers approximately 777,000 km2 (300,000 sq mi), extending into western Mongolia and eastern Kazakhstan. Formerly the term could cover a wider area, conterminous with the Dzungar Khanate, a state led by the native Oirats in the 18th century which was based in the area.