Khalkha Mongols

The Khalkha (Mongolian: Халх; Khalkh, Halh) is the largest subgroup of Mongol people in Mongolia since the 15th century. The Khalkha, together with Chahars, Ordos and Tumed, were directly ruled by Borjigin khans until the 20th century; unlike the Oirats, who were ruled by Dzungar nobles, or the Khorchins, who were ruled by Qasar's descendants.

The two original major Khalkha groups were ruled by the direct male line descendants of Dayan Khan. The Baarin, Khongirad, Jaruud, Baigut, and the O'zeed (Ujeed) became Dayan Khan's fifth son Achibolod's subjects, thus formed the Southern Five Halhs. The Qaraei, Jalairs, Olkhonud, Khatagin, Besut, Iljigin, Gorlos, Uriankhai, Sartuul, Tanghut, Khotogoid, Khuree, and Tsookhor became Dayan Khan's youngest (could be third) son Geresenje's (Mongolian: Гэрсэне Жалайр Хан) subjects, thus formed the "Аглагийн арван гурван хүрээ Халх" or Thirteen Khalkhas of the Far North.

There were also numerous direct descendants of Genghis Khan who had formed the ruling class of the Khalkha Mongols prior to the 20th century, but they were and still also regarded as Khalkha Mongols rather than belonging to a special unit.