United States signs treaty with the Yankton Sioux
- When
- 1857–1859
- Where
- Washington, D.C.; U.S. Government; Charles Mix County, South Dakota
- Episodes
- 4
The United States signed a treaty with the Yankton Sioux Tribe on April 19, 1858, in Washington, D.C. The agreement ceded most of eastern South Dakota to the U.S. government, establishing a reservation in Charles Mix County. Ratification occurred in February 1859, leading to the tribe's relocation in July 1859.
Episodes
- Negotiation in Washington
Yankton headmen traveled to Washington, D.C., in late 1857 to negotiate a treaty with the federal government.
- Signing of the Treaty
The treaty was signed on April 19, 1858, in Washington, D.C., by Charles E. Mix and Yankton chiefs.
- Ratification and Authorization
The Senate ratified the treaty on February 16, 1859, and President James Buchanan authorized it ten days later.
- Relocation to Reservation
The Yankton Sioux vacated ceded lands and moved onto the newly created reservation on July 10, 1859.
Background and detail
Background. Prior treaties, such as the 1851 Treaty of Traverse des Sioux, involved only specific bands, leaving Yankton claims unresolved. The Yankton and Yanktonai disputed annuities and land sales, viewing the Big Sioux River as a boundary. In late 1857, Yankton headmen traveled to Washington, D.C., to negotiate a new agreement addressing these territorial and financial grievances.
Treaty Terms. The treaty ceded 11 million acres in eastern South Dakota. It established a primary reservation in Charles Mix County and a one-mile square area at the Pipestone quarry. The Yankton pledged friendly relations, surrendered offenders, and submitted disputes to the President. The U.S. agreed to bear expenses for surveying the reservation and quarry.
Ratification and Relocation. The treaty was ratified by the Senate on February 16, 1859, and authorized by President James Buchanan ten days later. The agreement opened ceded territory for settlement, resulting in an unofficial local government. The Yankton Sioux vacated the ceded lands and moved onto the newly created reservation on July 10, 1859.
People involved
- Charles E. Mix · U.S. Commissioner
- Strike-the-Ree · Yankton Sioux Chief
Sources
- Yankton Treaty Wikipedia, revision of 2026-10-03
- Yankton Sioux Tribe Wikipedia, revision of 2026-10-02
Machine-drafted from the cited Wikipedia passages and checked by a reviewing model, not by a human editor. Every passage cites the revision it was written from; dates and places follow those passages.