The Cheyenne are an Indigenous people of the Great Plains. The Cheyenne comprise two Native American tribes, the Só'taeo'o or Só'taétaneo'o and the Tsétsėhéstȧhese ; the tribes merged in the early 19th century. Today, the Cheyenne people are split into two federally recognized nations: the Southern Cheyenne, who are enrolled in the Cheyenne and Arapaho Tribes in Oklahoma, and the Northern Cheyenne, who are enrolled in the Northern Cheyenne Tribe of the Northern Cheyenne Indian Reservation in Montana. The Cheyenne language belongs to the Algonquian language family.