
Viewing Fort Union Trading Post from the Missouri River bottoms one can imagine how grandiose the site would appear to weary steamboat travelers.
Photo: NPS Photo / Kris Baxter
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 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.
Located on North Dakota Highway 1804 right at the Montana and North Dakota state line. From Williston, ND, approximately 25 miles to the southwest via ND Highways 2 & 1804. From Sidney, MT, approximately 25 miles to the northeast, via MT Highways 200 & 58. Commercial flights and rental cars are available in both Williston, ND and Sidney, MT. Amtrak passenger train service and rental cars are available in Williston, ND.
Get directions →Weather in western North Dakota can be harsh, with extremes in temperature and sudden, violent storms. Be prepared for rapidly changing conditions. Summers are warm with average high temperatures in the 80s-90s May through September. Winters are cold with average lows in the single digits December through February. Wind is considerable year-round. Conditions can change quickly. Travelers should be aware of the potential for violent thunderstorms in the summer and the possibility of blizzards.

43rd Annual Fort Union Rendezvous
Fort Union Trading Post National Historic Site is set to come alive with the sights, sounds, smells and excitement of the American Frontier during the annual Rendezvous taking place June 18-21, 2026.

Prescribed Burn Planned at Fort Union Trading Post NHS
The National Park Service has scheduled a prescribed fire on federal lands in Williams County this Spring depending on environmental conditions. The current plan is to burn approximately 15 acres of grassland near the maintenance shop.