The Argun marks the border (established by the Treaty of Nerchinsk in 1689) between Russia and China for about 944 kilometres (587 mi), until it meets the Amur.

[2] In years with high precipitation, the normally exitless Hulun Lake may overflow at its northern shore, and the water will meet the Argun after about 30 kilometres (19 mi).

According to legend, it is the art of melting iron that has helped them escape from the mountain gorges on scope of the current Mongolian steppes, to the Kherlen (Kelulun) and Onon River.

Prior to the emergence of the Mongols, the Amur River basin was home to certain tribes of Jurchen people, who founded the Jin dynasty (1115–1234) in northern China.

Following the Russian conquest of Siberia in the 17th century, Russia-China relations were formalized in the 1689 Treaty of Nerchinsk, which established the Argun River as the China–Russia border.