Oirats (Mongolian: "ойрад", "ойрд", Oird; in the past, also Eleuths) are the westernmost group of the Mongols whose ancestral home is in the Altai region of western Mongolia. Although the Oirats originated in the eastern parts of Central Asia, the most prominent group today is located in Kalmykia, a federal subject of Russia, where they are called Kalmyks.Historically, the Oirats were composed of four major tribes: Dzungar (Choros or Olots), Torghut, Dörbet, and Khoshut.