The Treaties of 1866 were five separate agreements the federal government imposed on the Cherokee, Muscogee (Creek), Seminole, Choctaw, and Chickasaw Nations after factions within each tribe allied with the Confederacy during the Civil War. Washington used those alliances as leverage to force sweeping concessions: massive land cessions across the western half of Indian Territory, the abolition of slavery, citizenship for formerly enslaved people, rights of way for railroads, and the framework for an inter-tribal government. Their consequences reshaped Indian Territory so completely that disputes over what they mean still reach the Supreme Court.
Five Nations, Five Separate Treaties
Each of the Five Tribes negotiated its own agreement with federal commissioners, though the terms rhymed. The Seminole signed first on March 21, 1866.1Oklahoma State University Library. Treaty with the Seminole, 1866 The Choctaw and Chickasaw signed a joint treaty on April 28.2Oklahoma State University Library. Treaty with the Choctaw and Chickasaw, 1866 The Muscogee (Creek) followed on June 14.3Oklahoma State University Library. Treaty with the Creeks, 1866 The Cherokee agreement came last on July 19, delayed by the deep split between the nation’s loyalist and Confederate factions.4Oklahoma State University Library. Treaty with the Cherokee, 1866
Washington treated the five nations as if they had uniformly sided with the Confederacy. In fact, each had loyalist factions, and some tribal members had fought for the Union. The federal government largely ignored that distinction. Every agreement required the nation to declare permanent peace, accept potential military occupation, and recognize federal authority as supreme.3Oklahoma State University Library. Treaty with the Creeks, 1866
Land Cessions
The territorial demands were staggering. The treaties stripped the Five Tribes of roughly the western half of Indian Territory, ostensibly to house other tribes and formerly enslaved people.
The Seminole got the worst deal. They ceded their entire domain of about 2,169,080 acres at fifteen cents per acre, receiving $325,362, then had to buy a smaller replacement homeland of 200,000 acres from Creek-ceded lands at fifty cents per acre for $100,000.1Oklahoma State University Library. Treaty with the Seminole, 1866 They lost more than 90 percent of their land and paid over three times per acre for the replacement compared with what they received for the original.
The Muscogee (Creek) ceded the western half of their territory, about 3,250,560 acres, at thirty cents per acre for $975,168. The eastern half was designated the permanent Creek homeland, described in the treaty as “the reduced Creek reservation.”5Government Publishing Office. Treaty with the Creek Indians, 14 Stat. 786
The Choctaw and Chickasaw ceded the “Leased District” west of the 98th meridian for $300,000. That payment was not made directly. The federal government held it in trust at five percent interest, with release contingent on whether the tribes granted their Freedmen citizenship within two years.2Oklahoma State University Library. Treaty with the Choctaw and Chickasaw, 1866
The Cherokee cession followed a different pattern, carving out portions of Cherokee territory for the resettlement of other tribes rather than selling an entire western block at a flat rate.4Oklahoma State University Library. Treaty with the Cherokee, 1866
What Became of the Ceded Land
The treaties said the ceded territory would be used as homes for “other civilized Indians” the federal government chose to settle there.3Oklahoma State University Library. Treaty with the Creeks, 1866 Over the following years, numerous Plains and Midwestern tribes were relocated onto those western lands.
Not all of it went to new tribes. A large block in the center of present-day Oklahoma sat empty for more than two decades, becoming known as the Unassigned Lands. By the late 1870s, “Boomers” argued the empty land had reverted to the public domain and was eligible for homesteading. The standoff ended when the Creek Nation offered in January 1889 to relinquish any remaining claim. Congress authorized the opening, and on April 22, 1889, roughly 50,000 settlers raced in during the first Oklahoma Land Run.
Slavery Abolished, Freedmen Citizenship Divided
Every treaty required the immediate and permanent end of slavery within the signatory nation. What freedom meant in practice diverged sharply from treaty to treaty, and those differences still drive litigation.
Cherokee, Creek, and Seminole Terms
The Cherokee treaty granted Freedmen and their descendants “all the rights of native Cherokees,” provided they had been freed by their former owners or by law, had been in Cherokee territory at the start of the rebellion, and either currently resided there or returned within six months.4Oklahoma State University Library. Treaty with the Cherokee, 1866 That phrase was broad enough to cover voting, office-holding, and shares in communal property, though the treaty did not itemize those rights.
The Seminole treaty said persons of African descent and their descendants “shall have and enjoy all the rights of native citizens” and that tribal law would apply equally regardless of race.1Oklahoma State University Library. Treaty with the Seminole, 1866 The Creek treaty required parallel equal treatment for all adopted citizens regardless of color.3Oklahoma State University Library. Treaty with the Creeks, 1866
The Choctaw-Chickasaw Condition
The Choctaw-Chickasaw treaty was far less generous. It gave the two nations a two-year window to pass their own laws extending citizenship and forty acres of land to each Freedman. If they failed to act, the $300,000 held in trust for the Leased District cession would be redirected to fund the removal of Freedmen from the territory entirely. The United States committed to removing all willing Freedmen within ninety days after the two-year period expired; anyone who stayed or returned would receive nothing from that money and would stand as any other U.S. citizen in the territory.2Oklahoma State University Library. Treaty with the Choctaw and Chickasaw, 1866 Neither nation enacted the required legislation within two years, and the resulting legal limbo left Freedmen in those nations without clear citizenship rights for generations.
Where Freedmen Enrollment Stands Now
In 2017, a federal district court ruled that Cherokee Freedmen descendants hold a present right to citizenship in the Cherokee Nation under Article 9 of the 1866 treaty, “coextensive with the rights of Native Cherokees.” The court found that the Cherokee Nation’s sovereign power to define its membership was itself limited by the treaty it signed.6U.S. Government Accountability Office. Tribal Programs – Information on Freedmen Descendants of the Five Tribes
As of early 2026, Freedmen descendants are eligible to enroll in the Cherokee and Seminole Nations but remain excluded from the Chickasaw and Choctaw Nations.6U.S. Government Accountability Office. Tribal Programs – Information on Freedmen Descendants of the Five Tribes The Muscogee (Creek) Nation’s status is still unsettled; in March 2026, the Muscogee Nation Supreme Court ordered its citizenship board and principal chief to submit a second status report on Freedmen enrollment.
Railroad Rights of Way
The treaties opened Indian Territory to railroad construction. Terms varied, but each nation had to give up control over who could build across its land.
The Cherokee treaty granted a right of way up to two hundred feet wide across the entire nation to any company authorized by Congress, with another two hundred feet available at stations, water stops, and river crossings. Railroad employees working on construction, repairs, or operations were subject to federal Indian intercourse laws rather than tribal authority.4Oklahoma State University Library. Treaty with the Cherokee, 1866
The Creek treaty took a different approach. A congressionally authorized railroad, with the Interior Secretary’s approval, could purchase strips of unoccupied Creek land up to three miles wide on each side of the track. The price required mutual agreement between the Creek Nation and the railroad, subject to presidential approval. No land could transfer until the railroad was completed and accepted by the Interior Secretary as a first-class line.5Government Publishing Office. Treaty with the Creek Indians, 14 Stat. 786
Within a decade, lines like the Missouri, Kansas and Texas Railway were cutting through the territory, bringing non-tribal workers, commerce, and federal regulatory authority into lands the tribes had been promised in perpetuity.
The General Council of Indian Territory
Several of the treaties required the creation of an inter-tribal legislative body called the General Council. The Creek treaty’s Article X laid out the structure. The council would consist of delegates elected by each tribe lawfully residing in Indian Territory, with representation based on population: one delegate per tribe plus an additional delegate for every thousand members. The Interior Secretary would order a census to determine representation before the first session.5Government Publishing Office. Treaty with the Creek Indians, 14 Stat. 786
On paper, the council’s jurisdiction was broad. It could legislate on relations between resident tribes, govern extradition among the nations, administer justice in disputes involving non-Indians, and authorize internal improvements like roads and bridges. Sessions were capped at thirty days per year, with the Interior Secretary able to call special sessions. It was, in effect, a federally designed territorial legislature.
In 1870, delegates met at the Creek capital of Okmulgee and drafted an inter-tribal constitution built on the treaty requirements.7Oklahoma Historical Society. Okmulgee Constitution The Okmulgee Constitution was never ratified by enough tribes to take effect. The General Council concept ultimately failed because the tribes recognized it as a tool for dissolving their separate governments into a single territorial unit Washington could more easily manage.
Why the Treaties Still Matter
The Supreme Court has treated the 1866 treaties as living documents with binding force. In McGirt v. Oklahoma (2020), the Court held that the Creek reservation established by the original treaties and preserved, though reduced, by the 1866 agreement had never been disestablished by Congress. Treaty language promising that the remaining Creek lands would “be forever set apart as a home for said Creek Nation” was enough to constitute a formal reservation, even without that specific word.8Supreme Court of the United States. McGirt v. Oklahoma, 591 U.S. ___ (2020)
The practical effect was enormous. Because the reservation still existed, Oklahoma lacked jurisdiction to prosecute crimes committed by tribal members within its boundaries. The decision covered roughly the eastern half of Oklahoma, and later rulings extended the same logic to the other four nations’ reservations.
Two years later, in Oklahoma v. Castro-Huerta (2022), the Court held that states have concurrent jurisdiction with the federal government to prosecute crimes committed by non-Indians against Indians in Indian country, overturning a longstanding assumption that states had no such authority.9Supreme Court of the United States. Oklahoma v. Castro-Huerta, 597 U.S. ___ (2022) The decision clawed back part of what McGirt had recognized, and tribal advocates called it a direct strike against tribal sovereignty within treaty-established boundaries.
Between the Freedmen citizenship disputes, jurisdictional battles over criminal law, and land-title questions affecting millions of acres, the Treaties of 1866 remain among the most consequential and contested documents in the relationship between the United States and tribal nations. Their central tension has never been resolved: they simultaneously affirmed that the tribes would hold their remaining lands forever and created the mechanisms through which those same lands would be opened, divided, and brought under federal control.