a river in Khabarovsk Krai, RSFSR, a major left-bank tributary of the lower Amur. It is 723 km long, and its basin covers 55,500 sq km. It is formed by the confluence of the rivers Aiakit and Suluk (Kholuk) on the slopes of the Bureya range.

In the upper reaches the Amgun’ has the character of a mountain river, but it is primarily a typical lowland river. It flows through a broad valley of swampy taiga, winding unsteadily and dividing into many channels. There are many small islands and shoals in the lower reaches. Its chief tributary is the Nimelen. Permafrost is widespread in the Amgun’ basin. The feed water comes primarily from rain.

The Amgun’ has a long high-water season, from June to September, which is caused by a series of floods; in the winter it is at a constant low level. The average annual flow rate is 500 cu m per sec (193 km from the mouth). There is ice from late October to early May. The Amgun’ is navigable, except in the upper reaches, and rich in fish (Siberian salmon, humpback salmon, sturgeon, carp, and others).