Buir Lake is a freshwater lake that straddles the border between Mongolia and China. It lies within the Buir Lake Depression. The Chinese city of Hulunbuir is named after both this lake and Hulun Lake, which lies entirely on the Chinese side of the border in Inner Mongolia.
In 1388, Ming forces under Lan Yu won a major victory over the Northern Yuan on the Buir Lake region. Northern Yuan ruler Tögüs Temür tried to escape but was killed shortly afterwards.
The Khalkh River (also spelled as Khalkha River or Halaha River; Mongolian: Халх гол; Chinese: 哈拉哈 Ha-la-ha; Ha-lo-hsin Ho) is a river in eastern Mongolia and northern China's Inner Mongolia region. The river is also referred to with the Mongolian genitive suffix -iin as the Khalkhin Gol, or River of Khalkh.
The river's source is the western slopes of the Greater Khingan mountains of Inner Mongolia. In its lower course, it forms the boundary between China's Inner Mongolia, and the Mongolian Republic until around 48°01′59″N 118°08′03″E / 48.033179°N 118.134290°E, the river splits into two distributaries. The left branch (the Halh River proper) flows into the Buir Lakeat 47°53′44″N 117°50′08″E / 47.895556°N 117.835556°E; discharge from that lake at 47°57′00″N 117°48′51″E / 47.950011°N 117.814270°E)is known as the Orshuun Gol (Mongolian: Оршуун гол, Chinese: 乌尔逊河; pinyin: Wūěrxùn Hé). The right branch, known as the Shariljiin Gol (Mongolian: Шарилжийн гол) flows directly into the Orshuun Gol at 48°04′12″N 117°45′20″E / 48.069891°N 117.755433°E. Orhuun connects the Buir Lake with the Hulun Lake. The Chinese–Mongolian border then follows the Shariljiin Gol for about an equal distance.
Hulunbuir or Hulun Buir is a prefecture-level city in northeastern Inner Mongolia, China. Its administrative center is located at Hailar District, its largest urban area. Major scenic features are the high steppes of the Hulun Buir grasslands, the Hulun and Buir lakes (the latter partially in Mongolia), and the Khingan range. Hulun Buir borders Russia to the north and west, Mongolia to the south and west, Heilongjiang province to the east and Hinggan League to the direct south. Hulunbuir is a linguistically diverse area: next to Mandarin Chinese, Mongolian dialects such as Khorchin and Buryat, the Mongolic language Daur, and some Tungusic languages, including Oroqen and Solon, are spoken there.