The Treaty of Lancaster, in which the Iroquois cede lands between the Allegheny Mountains and the Ohio River to the British colonies, was signed in Lancaster, Pennsylvania.

The Six Nations land cessions were a series of land cessions by the Haudenosaunee and Lenape to Europeans during the late 17th and 18th centuries. They ceded large amounts of land, including both recently conquered territories acquired from other indigenous peoples in the Beaver Wars, and their own 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.

The Iroquois, also known as the Five Nations, and later as the Six Nations from 1722 onwards; alternatively referred to by the endonym Haudenosaunee are an Iroquoian-speaking confederacy of Native Americans and First Nations peoples in northeast North America. They were known by the French during the colonial years as the Iroquois League, and later as the Iroquois Confederacy, while the English simply called them the "Five Nations". Their country has been called Iroquoia and Haudenosauneega in English, and Iroquoisie in French. The peoples of the Iroquois included the Mohawk, Oneida, Onondaga, Cayuga, and Seneca. After 1722, the Iroquoian-speaking Tuscarora people from the southeast were accepted into the confederacy, from which point it was known as the "Six Nations".

The Allegheny Mountain Range — also spelled Alleghany or Allegany, less formally the Alleghenies — is part of the vast Appalachian Mountain Range of the Eastern United States and Canada. Historically it represented a significant barrier to westward land travel and development. The Alleghenies have a northeast–southwest orientation, running for about 300 miles (480 km) from north-central Pennsylvania southward, through western Maryland and eastern West Virginia.