Fort Henry on the Missouri River, located at the mouth of the Yellowstone where it enters the Missouri, was established on October 1, 1822, by a party of men led by Major Andrew Henry, who mounted the expedition for the purpose of establishing a fur trade outpost for an area which now encompasses most of Montana, western North Dakota, parts of Wyoming, into Canada.[1] [2] The site of the fort, which was abandoned in 1823, is approximately southwest of Williston, North Dakota near the Montana - North Dakota state line.
Other short-lived forts were established by Henry on his earlier expedition with the Missouri Fur Company. In the spring of 1810, the first Fort Henry[3] was built at the Three Forks of the Missouri River near-present day Three Forks, Montana, but was abandoned shortly thereafter.[4] A second Fort Henry[5] was established during the fall of 1810 on Henry's Fork of the Snake River in present-day southeastern Idaho; it was abandoned in 1811.[6]