Fort Union Trading Post National Historic Site

https://www.nps.gov/fous/index.htm

The Grandest Fort on the Upper Missouri River.

Between 1828 and 1867, Fort Union was the most important fur trade post on the Upper Missouri River. Here, the Assiniboine and six other Northern Plains Indian Tribes exchanged buffalo robes and smaller furs for goods from around the world, including cloth, guns, blankets, and beads. A bastion of peaceful coexistence, the post annually traded over 25,000 buffalo robes and $100,000 in merchandise.