[1][9] If including its main stem tributary, the Argun, the Amur is 4,444 km (2,761 mi) long,[9][2] making it the world's tenth longest river.

[1] The river rises in the hills in the western part of Northeast China at the confluence of its two major affluents, the Shilka and the Argun (or Ergune), at an elevation of 303 metres (994 ft).

[17] It flows east forming the border between China and Russia, and slowly makes a great arc to the southeast for about 400 kilometres (250 mi), receiving many tributaries and passing many small towns.

[18] Afterwards it continues to flow south until, between the cities of Blagoveshchensk in Russia and Heihe in China, it widens significantly as it is joined by one of its most important tributaries the Zeya.

At the confluence with the Songhua the river turns northeast, now flowing towards Khabarovsk, where it joins the Ussuri and ceases to define the Russia–China border.

Now the river spreads out dramatically into a braided character, flowing north-northeast through a wide valley in eastern Russia, passing Amursk and Komsomolsk-on-Amur.

Shortly after, the Amur turns sharply east and into an estuary at Nikolayevsk-on-Amur, about 20 kilometres (12 mi) downstream of which it flows into the Strait of Tartary.

For many[quantify] centuries, inhabitants of the Amur Valley comprised the Tungusic (Evenki, Solon, Ducher, Jurchen, Nanai, Ulch), Mongol (Daur) people, some Ainu and, near its mouth, the Nivkhs.

The Chinese-language term Yúpí Dázi 魚皮韃子 ("Fish-skin Tatars") came to apply to the Nanais and related groups as well, owing to their traditional clothes made of fish skins.

[26] The Mongols, ruling the region as the Yuan dynasty, established a tenuous military presence on the lower Amur in the 13th and 14th centuries; ruins of a Yuan-era temple have been excavated near the village of Tyr.

Expeditions headed by the eunuch Yishiha reached Tyr several times between 1411 and the early 1430s, re-building (twice) the Yongning Temple and obtaining at least the nominal allegiance of the lower Amur's tribes to the Ming government.

[citation needed] At the time, the Manchus were busy with conquering China; but a few decades later, during the Kangxi era of 1661–1722, they turned their attention to their north-Manchurian backyard.

Aigun was re-established near the supposed Ming site in about 1683–84, and a military expeditions went upstream to dislodge the Russians, whose Albazin establishment deprived the Manchu rulers of the tribute of sable pelts that the Solons and Daurs of the area would supply otherwise.

The Treaty of Nerchinsk, concluded in 1689, marked the end of the hostilities: it left the entire Amur valley, from the convergence of the Shilka and the Ergune downstream, in Chinese hands.

[34]The Amur region remained a relative backwater of the Qing Empire for the next century and a half, with Aigun being practically the only major town on the river.

Flowing across northeast Asia for over 4,444 kilometres (2,761 mi) (including its two tributaries), from the mountains of northeastern China to the Sea of Okhotsk (near Nikolayevsk-na-Amure), it drains a remarkable watershed that includes diverse landscapes of desert, steppe, tundra, and taiga, eventually emptying into the Pacific Ocean through the Strait of Tartary, where the mouth of the river faces the northern end of the island of Sakhalin.