Because of its inherent multidisciplinarity and conceptual flexibility, trauma theory has, from the start, been subject to ongoing revisions and redefinitions. This essay expands the notion of trauma as resulting from unassimilable, life-threatening, past events by conceptualizing trauma as resulting from the envisaged imminent annihilation of the known world. This apocalyptic trauma is embedded in American literature and closely tied to the politics of mourning dramatized in narratives of loss and melancholia but also in narratives of political activism and regeneration. This essay discusses apocalyptic expressions related to the trauma of the loss of the culture of the Old South in William Faulkner’s work, to the trauma of dispossession and cultural erasure in Chicano/a literature, and to the trauma of envisaged global annihilation in American eco-poetry.