Although the region had been occupied since the Mesolithic, the first fortifications were built at Amnya I some time after 6100 BCE, preceding a main settlement phase for both sites for much of the 6th millennium.

Although typically associated with agrarian and pastoralist societies, a long archaeological tradition of fortification building is present among hunter-gatherers of the Western Siberia taiga, with nearly one hundred known sites over an 8000 year period stretching from the Neolithic to the Russian conquest of the 16th and 17th centuries CE.

[a] Eight fortified sites dating to the Stone Age are attested in Western Siberia, the earliest known fortifications in Northern Eurasia.

Kholms, large earthen mounds frequently containing human skulls and figurines, are also attested in the region during this period, interpreted as ritualistic or sacrificial sites.

These sites typically comprised a central dwelling or complex fortified with earthworks and palisades, adjacent to a cluster of additional pit-houses.

With some later exceptions, this fort building tradition largely evaporated during the Chalcolithic c. 4000 BCE, before reviving as a series of individually fortified dwellings during the early Bronze Age.

[3] The Amnya complex is situated at the edge of a promontory 4.5 kilometres (2.8 miles) southeast of the village of Kazym [ru] in the Beloyarsky District of the Khanty-Mansi Autonomous Okrug.

Amnya I, at the tip of the promontory, comprises a group of ten pit-houses surrounded by a series of raised banks and ditches enclosing the construction.

[10] The emergence of significantly increased settlement in Western Siberia during the late 7th millennia BCE has been tentatively linked to the 8.2-kiloyear event.

[13] Permanent structures and large numbers of weapons, including 28 polished arrowheads, recovered from the site suggest a degree of social stratification in the region, of which the residents of Amnya were elites.

[12] Around 45 pottery vessels have been found at the sites, divided between two ornamental traditions, one featuring prickled incised indentation, and the other flatter type stamped with combs.

[15] A smaller neolithic site within the region, Kirip-Vis-Yugan-2, has been culturally linked to the Amnya complex due to the similarity of collected artifacts.

[19][20] Alongside similar structures found in the pre-Columbian Americas, the Amnya complex and broader Western Siberian fortification-building tradition has increasingly informed study of fortifications built by hunter-gatherers.