Fort Union Trading Post National Historic Site
|Location||McKenzie and Williams counties, North Dakota, and Richland and Roosevelt counties, Montana |
|Nearest city||Williston, North Dakota|
FORT UNION TRADING POST NATIONAL HISTORIC SITE Latitude and Longitude:
|Area||444 acres (1.80 km2)|
|Architect||American Fur Company|
|Architectural style||Greek Revival, Other|
|Website||Fort Union Trading Post National Historic Site|
|NRHP reference #||66000103|
|Added to NRHP||October 15, 1966 |
|Designated NHL||July 4, 1961 |
|Designated NHS||June 20, 1966|
Fort Union Trading Post National Historic Site is the site of a partially reconstructed trading post on the Missouri River and the North Dakota/ Montana border, 25 miles from Williston, North Dakota. It is one of the earliest declared National Historic Landmarks in the United States. The fort, possibly first known as Fort Henry or Fort Floyd, was built in 1828 or 1829 by the Upper Missouri Outfit managed by Kenneth McKenzie and capitalized by John Jacob Astor's American Fur Company. 
Fort Union was the most important fur trading post on the upper Missouri until 1867. It was instrumental in developing the fur trade in Montana. Here Assiniboine, Crow, Cree, Ojibwe, Blackfoot, Hidatsa, Lakota, and other tribes traded buffalo robes and furs for trade goods including items such as beads,  clay pipes,  guns, blankets, knives, cookware, cloth, and alcohol. Historic visitors to the fort included John James Audubon, George Catlin, Sha-có-pay, Father Pierre DeSmet, Sitting Bull, Karl Bodmer, Hugh Glass, and Jim Bridger.
The site was declared a National Historic Landmark in 1961   and was named Fort Union Trading Post by the National Park Service to differentiate it from Fort Union National Monument, a historic frontier Army post in New Mexico.
Today, the partially reconstructed Fort Union interprets how portions of the fort may have looked in 1851, based on archaeological excavations as well as sketches by contemporaries, including Rudolf Kurz, the post clerk in 1851.
- Fort Buford, nearby site
- Missouri-Yellowstone Confluence Interpretive Center
- Fur trade in Montana
- List of National Historic Landmarks in Montana
- National Register of Historic Places listings in Roosevelt County, Montana
- List of National Historic Landmarks in North Dakota
- National Register of Historic Places listings in Richland County, North Dakota
- National Park Service (April 17, 2015), Weekly List of Actions Taken on Properties: 4/06/15 through 4/10/15, retrieved April 23, 2015.
- National Park Service (2007-01-23). "National Register Information System". National Register of Historic Places. National Park Service.
- "Fort Union Trading Post National Historic Site". National Historic Landmark summary listing. National Park Service. Archived from the original on 2011-06-06. Retrieved 2008-01-21.
- John Matzko, Reconstructing Fort Union (University of Nebraska Press, 2001), 11.
- De Vore, Steven LeRoy, 1992. BEADS of the BISON ROBE TRADE: The Fort Union Trading Post Collection. Friends of Fort Union Trading Post, Williston, North Dakota. http://www.nps.gov/archive/fous/booksplus.html
- Sudbury, J. Byron, 2009. Politics of the Fur Trade: Clay Tobacco Pipes at Fort Union Trading Post (32WI17). Historic Clay Tobacco Pipe Studies Research Monograph 2. 225 pages. Clay Pipes Press, Ponca City, Oklahoma 74602-2282 USA. http://www.claypipes.com/FortUnion.htm
- Roy A. Matteson (October 5, 1951) National Survey of Historic Sites and Buildings: Fort Union, National Park Service and Accompanying 1 photo from July 1948.