The lands near the confluence of the Ussury and the Amur, where today's Khabarovsk stands, have been populated by many centuries by Tungusic people, probably related to the Jurchens of the past and/or the Nanais of the present day. Chinese expeditions reached this area as early as the first half of the 15th century, when the fleets of the Ming eunuch Yishiha sailed several times from Jilin City all the way to Tyr on the lower Amur.
In the middle of the 17th century the Amur Valley became the scene of hostilities between the Russian Cossacks, trying to expand into the region and to collect tribute from the natives, and the rising Manchu Qing Dynasty, intent on securing the region for itself.
The Russian explorers and raiders of the 1650s set up a number of more or less fortified camps (ostrogs) on the Amur; most of them were in use for only a few months, and later destroyed. It is usually thought that the first such camp in the general area of today's Khabarovsk was the fortified winter camp named Achansk , built by the Cossacks of Yerofey Khabarov in September 1651 after they had sailed to the area from the upper Amur. The fort was named after the local tribe whom Khabarov's people called "Achans". Already on October 8 the fort was unsuccessfully attacked by joint forces of Achans and Duchers (who had good reasons to hate the Cossacks, due to their rather heavy-handed tribute-extraction tactics), while many Russians were out fishing. In late November, Khabarov's people undertook a three-day campaign against the local chief Zhakshur (whose name is also known in a more Russian version, Zaksor (Заксор)), collecting a large amount of tribute and announcing that the locals were now subjects of the Russian Czar. Similar campaign was waged later in winter against the Ducher chief Nechiga (Нечига), farther away from Achansk. On March 24 (or 26) 1652, Fort Achansk was attacked by Manchu cavalry, led by Ninguta's commander Haise, reinforced by Ducher auxiliaries, but the Cossacks stood their ground in a day-long battle and even managed to seize the attackers' supply train. Once the ice on the Amur broke in the spring of 1652, Khabarov's people destroyed their fort and sailed away.