Khentii Mountains in the context of "Bogd Khan Uul Biosphere Reserve"

The Mongolian Plateau or Altai Plateau is an inland plateau in East Asia covering approximately 3,200,000 square kilometers (1,200,000 sq mi). It is bounded by the Greater Hinggan Mountains in the east, the Yin Mountains to the south, the Altai Mountains to the west, and the Sayan and Khentii mountains to the north. The plateau includes the Gobi Desert as well as dry steppe regions. It has an elevation of roughly 1,000 to 1,500 meters (3,300 to 4,900 ft), with the lowest point in Hulunbuir and the highest point in the Altai.

Politically, the plateau spans all of Mongolia, along with parts of China and Russia. Inner Mongolia and parts of the Dzungarian Basin in Xinjiang encompass the Chinese portion of the plateau. In Russia, the plateau forms Transbaikal, part of Buryatia, and the southern Irkutsk Oblast. The Mongolian Plateau comprises the majority of the area known as the Mongol heartland.

The Tuul River or Tula River (/ˈtuːl/; Mongolian: Туул гол, Tuul gol, pronounced [ˈtʰʊːɮ ɢɔɮ]; in older sources also Tola) is a river in central and northern Mongolia. Sacred to the Mongols, the Tuul is generally called the Hatan Tuul (Mongolian: Хатан Туул, [ˈχaʰtəɴ tʰʊːɮ]; lit. "Queen Tuul"). It is 882.8 kilometres or 549 miles long and drains an area of 49,840 square kilometres or 19,240 square miles. The Secret History of the Mongols (1240 AD) frequently mentions a "Black Forest of the Tuul River" where the palace of Ong Khan was located.

The river originates in the Khan Khentii Strictly Protected Area in the Khentii Mountains, in the Erdene sum of Töv aimag.From there, it travels southwest until it reaches the territory of Ulaanbaatar. Its water runs through the southern part of the capital city of Mongolia, continuing in a western direction in large loops. When it meets the border of Bulgan aimag it turns north, running along that border. After it enters Selenge aimag, it discharges into the Orkhon River near the sum center of Orkhontuul sum.

Khentii (Mongolian: Хэнтий [xe̝ntʰí]), named after the Khentii Mountains, is one of the 21 provinces of Mongolia, located in the eastern part of the country. Its capital is Chinggis City. It is best known as the birthplace (and likely final resting place) of Genghis Khan.

Khamag Mongol (Mongolian: ᠬᠠᠮᠤᠭ
ᠮᠣᠩᠭᠣᠯ Хамаг Монгол, lit. 'Whole Mongol'; Chinese: 蒙兀國) was a loose Mongolic tribal confederation on the Mongolian Plateau in the 12th century. It is sometimes considered to be a predecessor state to the Mongol Empire.

The existence of a somewhat mysterious tribal power known in Mongol tradition as Khamag Mongol Uls is recorded in sources of the Khitan-led Liao dynasty. After the fall of the Liao dynasty in 1125, the Khamag Mongols began to play an important role on the Mongolian plains. They occupied one of the most fertile lands of the country, the basins of the river Onon, Kherlen and Tuul Rivers in the Khentii Mountains. The Taichiud (Cyrillic: Тайчууд) was one of the three core tribes in the Khamag Mongol Khanate of Mongolia during the 12th century and whose people lived in the southern part of Siberia's modern-day Zabaykalsky Krai. The present-day Zabaykalsky Krai and the Khentii Province of Mongolia were the core regions of the Khamag Mongol Khanate. The Khamags consisted of the three core clans Khiyad, Taichuud, and Jalairs.