1770s Pacific Northwest smallpox epidemic

The first known smallpox epidemic to strike the native peoples of the coastal and interior Pacific Northwest arrived in the early 1770s, devastating large swathes of the population and causing significant demographic collapse – both from the disease itself and corresponding malnutrition from the deaths of hunters within tribes. Poorly attested due to a lack of consistent European presence during the period, it most likely originated from Bruno de Heceta and Bodega y Quadra's 1775 expedition to the Northwest Coast, spreading as far inland as the Bitterroot Salish territories in western Montana and as far north as the Tlingit at Sitka.

Source: Wikipedia — 1770s Pacific Northwest smallpox epidemic (CC BY-SA 4.0)