The Seneca are a group of Indigenous Iroquoian-speaking people who historically lived south of Lake Ontario, one of the five Great Lakes in North America. Their nation was the farthest to the west within the Six Nations or Iroquois League (Haudenosaunee) in New York before the American Revolution. For this reason, they are called “The Keepers of the Western Door.”

Seneca is the language of the Seneca people, one of the Six Nations of the Hodinöhsö꞉niʼ ; it is an Iroquoian language, spoken at the time of contact in the western part of New York. While the name Seneca, attested as early as the seventeenth century, is of obscure origins, the endonym Onödowáʼga꞉ translates to "those of the big hill." About 10,000 Seneca live in the United States and Canada, primarily on reservations in western New York, with others living in Oklahoma and near Brantford, Ontario. As of 2022, an active language revitalization program is underway.