Fort Osage

Fort Osage
U.S. National Register of Historic Places
U.S. National Historic Landmark District
Fort Osage from the west. The "factory" trading post is on the left.
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Location	Sibley, Missouri
Coordinates	39°11′15″N 94°11′32″W / 39.187562°N 94.192121°W / 39.187562; -94.192121
Built	1808[1]
NRHP reference No.	66000418
Significant dates
Added to NRHP	October 15, 1966[2]
Designated NHLD	November 5, 1961[3]

Fort Osage (also known as Fort Clark or Fort Sibley) was an early 19th-century factory trading post run by the United States Government in western Missouri on the American frontier; it was located in present-day Sibley, Missouri. The Treaty of Fort Clark, signed with certain members of the Osage Nation in 1808, called for the United States to establish Fort Osage as a trading post and to protect the Osage from tribal enemies.

It was one of three forts established by the U.S. Army to establish control over the newly acquired Louisiana Purchase territories west of the Mississippi River. Fort Madison in SE Iowa was built to control trade and pacify Native Americans in the Upper Mississippi River region. Fort Belle Fontaine, near St. Louis, controlled the mouth of the Missouri at the Mississippi.^[4]

Fort Osage ceased operations in the 1820s as the Osage in subsequent treaties had ceded the rest of their land in Missouri to the US. A replica of the fort was constructed on the site between 1948 and 1961. The Fort Osage school district (including Fort Osage High School), which serves northeast Independence and the surrounding area, was named after it.