Yellowstone Expedition

The Yellowstone expedition was a frontier expedition authorized in 1818 by United States Secretary of War John C. Calhoun to establish a military fort or outpost near present-day Bismarck, North Dakota at the mouth of the Yellowstone River. Sometimes called the Atkinson-Long Expedition, it led to the creation of Fort Atkinson (Nebraska), the first United States Army post to be established west of the Missouri River, but was otherwise a costly failure, stalling near Council Bluffs, Iowa.

Secretary Calhoun stated the expedition was a "part of a system of measures" to maintain northwestern trade, describing its objects as "the protection of our northwestern frontier and the greater extension of our fur trade.". The economic condition had halted in the states due to growing dissent over state issues that were to lead up to the American Civil War, and this gave the expedition military as well as economic reasons.

Starting from St Louis, Missouri, the expedition aimed to establish a series of forts along the Missouri River on the way upstream to the Yellowstone (principal tributary of the upper Missouri). These forts would increase American presence in the fur trade and would also counteract British influence on the northern plains. The first fort was to be at the Council Bluff (not to be confused with Council Bluffs, Iowa, 20 miles to the south), the site previously used for an 1804 council between the Lewis and Clark Expedition and members of the Oto and Missouria Native American tribes. William Clark had recommended the high bluff overlooking the Missouri River to the US government as a suitable location to build a fort.

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