Certain chiefs and braves of the Sioux nation, while visiting Washington, ceded to the United States all their lands east of the Mississippi and all their islands in the river.

The evidence

• “18. Certain chiefs and braves of the Sioux nation of the Mississippi, while visiting Washington, September 29, 1837, ceded to the United States all their lands east of the Mississippi, and all their islands in said river.”

  1879-history-of-rock-county/04-wisconsin-railroads-commerce-health-statistics.md, PDF p. 213 / book p. 217

  Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.

  Grade A: Found on a page of one of our sources