Buir Lake is a freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

 and partly in Inner Mongolia

Inner Mongolia

Inner Mongolia is an autonomous region of the People's Republic of China, located in the northern region of the country. Inner Mongolia shares an international border with the countries of Mongolia and the Russian Federation...

, China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. It lies within the Buir Lake Depression. Together with Hulun Lake (Dalai Lake), it gives the name to Hulun Buir steppe and region.

In 1388, Ming forces under Lan Yu

Lan Yu (general)

Lan Yu was a Chinese general who contributed to the founding of the Ming Dynasty. His ancestral home was in present-day Dingyuan County, Anhui. In 1393 Lan was suspected and accused of plotting a rebellion and eventually put to death by the Hongwu Emperor...

 won a major victory over the Northern Yuan Dynasty on the Buir Lake region. Northern Yuan ruler Tögüs Temür tried to escape but was killed shortly afterwards.