The Osage Nation is a Native American Siouan-speaking tribe in the United States that originated in the Ohio River valley in present-day Kentucky. After years of war with invading Iroquois, the Osage migrated west of the Mississippi River to their historic lands in present-day Arkansas, Missouri, Kansas, and Oklahoma by the mid-17th century. At the height of their power in the early 18th century, the Osage had become the dominant power in their region, controlling the area between the Missouri and Red rivers. They are a federally recognized tribe and based mainly in Osage County, Oklahoma, coterminous with their reservation. Members are found throughout the country. read more