Archaeological narratives have traditionally associated the rise of social and political 'complexity' with the emergence of agricultural societies. However, this framework neglects the innovations of the hunter-gatherer populations occupying the Siberian taiga 8000 years ago, including the construction of some of the oldest-known fortified sites in the world. Here, the authors present results from the fortified site of Amnya in western Siberia, reporting new radiocarbon dates as the basis for a re-evaluation of the chronology and settlement organisation. Assessed within the context of the changing social and environmental landscape of the taiga, Amnya and similar fortified sites can be understood as one facet of a broader adaptive strategy.