
Fort Union Trading Post from the Bodmer Overlook, on the cover of the park's Geologic Resources Inventory report. National Park Service.
The site
Fort Union Trading Post National Historic Site lies on the upper Missouri River along the Montana–North Dakota border, where McKenzie and Williams counties, North Dakota, meet Richland and Roosevelt counties, Montana.
- Authorized: June 20, 1966.
- Size: about 178 hectares (440 acres).
- What it remembers: the Fort Union fur trading post (1828–1867), the main commercial hub of the American Fur Company and the longest-lasting fur trading post in the United States.
Despite its name, Fort Union was never military. It was a business, where traders and Northern Plains tribes — Assiniboine, Crow, Cree, Ojibwa, Blackfeet, Hidatsa, Mandan, Arikara and others — exchanged buffalo hides and other furs for beads, cloth, blankets, kettles, guns and knives. It shaped the exploration of the frontier and stood for an economically rewarding relationship between Northern Plains tribes and European Americans.
Today a full-scale reconstruction of the 1850s fort includes its 5 m (17 ft) palisade walls, a trade house, the clerk's office and the lavish Bourgeois House.

The site during one of its annual summer rendezvous. NPS photo by Emily Sunblade.
The rocks beneath it
The site lies in the Great Plains physiographic province — a vast, plateau-like region of lowlands and scattered mountains running from Mexico to Canada, and east from the Rocky Mountains to the Missouri Escarpment in the central Dakotas (Keefer 1974).
Its river landscape of bluffs, terraces and floodplain is made entirely of young rock and sediment (Graham 2015a):
| Unit | Where | What it is |
|---|---|---|
| Fort Union Formation (Paleocene) | under the site north of the Missouri | sandstone, siltstone and mudstone |
| Alluvium and colluvium (Holocene) | the southern part of the site, on the Missouri's floodplain | young, loose deposits |
Named for the fort: Meek and Hayden named the Fort Union Formation in 1862 after Old Fort Union, near the mouth of the Yellowstone River — but no formal type section (stratotype) has ever been designated for it.

The Geologic Resources Inventory's geologic map of the site. National Park Service.
Maps, reports and soils
The Park Service's Geologic Resources Inventory makes digital geologic maps and reports for more than 270 natural resource parks. Its products for Fort Union — scoping summaries, digital geologic maps, reports and posters — are on the NPS DataStore. A completed Soil Resources Inventory for the site is there too (saved search).
More: Fort Union Trading Post — natural features and ecosystems · NPS Geodiversity Atlas.
Sources
Based on "NPS Geodiversity Atlas—Fort Union Trading Post National Historic Site, North Dakota and Montana," National Park Service; a work of the United States government in the public domain.
이용 허락: CC0 1.0 (퍼블릭 도메인) · 출처 www.nps.gov
1
0
0
0

코멘트






