Humans have evolved mechanisms for the detection and management of possible threats in order to abate their negative consequences for fitness. Internally generated (‘detached’) cognition may have evolved in part because of its contributions to this broad function, but important questions remain about its role in threat management. In this article, we therefore present a taxonomy of threat-related internally generated cognition comprising episodic and semantic formats of memory and prospection. We address the proximate mechanisms of each of the capacities in this taxonomy, and discuss their respective contributions to adaptive threat management in humans. For instance, mental time travel empowers people to contemplate and learn from threats experienced long ago, as well as to plan for dangers that might arise in the distant future. However, despite their functional benefits, these thought processes are also central to contemporary anxiety disorders and may be a potent source of distress.