The Six Nations land cessions were a series of land cessions by the Haudenosaunee and Lenape which ceded large amounts of land, including both recently conquered territories acquired from other indigenous peoples in the Beaver Wars and ancestral lands to the Thirteen Colonies and the United States. The land ceded covered, partially or in the entire, the U.S. states of New York, Pennsylvania, Maryland, Virginia, West Virginia, Kentucky, Ohio, Tennessee and North Carolina. They were bordered to the west by the Algonquian lands in the Ohio Country, Cherokee lands to the south, and Muscogee and Choctaw lands to the southeast.

The land cessions were accomplished through a series of purchases and treaties negotiated between the Haudenosaunee and the Province of New York (and after the American Revolution, the United States government) between 1682 and 1797. In the Nanfan Treaty of 1701, the Haudenosaunee had ceded their lands north and west of the Ohio River to the Thirteen Colonies, which were in part obtained from the Beaver Wars in the late 17th century. During the period of Indian removal in the early 19th century by the U.S. government, a majority of the Oneida, one of the tribes which made up the Haudenosaunee, migrated to the state of Wisconsin. Other Haudenosaunee migrated to Ontario or Oklahoma. As of the 21st century, the Haudenosaunee live in 20 settlements and 8 reservations in New York, Wisconsin, Oklahoma, Ontario and Quebec.