1837–1838 smallpox epidemic
1837 CE.
Shown on the map at 37.000°, -97.000°.
Between 1836 and 1840, smallpox became widespread across the Great Plains. The epidemic reached its height following the spring of 1837, when an American Fur Company steamboat, the SS St. Peter's, carried infected people and supplies up the Missouri River in the Midwestern United States. The disease spread rapidly to indigenous populations with no natural immunity, causing widespread illness and death across the Great Plains, especially in the Upper Missouri River watershed. More than 17,000 Indigenous people died along the Missouri River alone, with some bands becoming nearly extinct. One Native tribe majorly affected by the smallpox epidemic was the Mandan tribe. The Mandans traditionally lived along the Missouri River. They had an extraordinarily rich culture, due to them hosting many European and American travelers. The Mandan villages consisted of twelve to a hundred lodges and were well organized with a hierarchy of leaders. In 1750, there were about nine large Mandan villages; however, by the start of the 19th century, the smallpox epidemic decreased the tribe to only two villages.
Text from the Wikipedia article 1837 Great Plains smallpox epidemic, licensed CC BY-SA 4.0.