Cheyenne are a Native American people of the Great Plains, who are of the Algonquian language family.

The Cheyenne Nation is composed of two united tribes, the Só'taeo'o (more commonly as Sutaio) and the Tsétsêhéstâhese (more commonly as Tsitsistas).

The Cheyenne are thought to have branched off other tribes of Algonquian stock around the Great Lakes in present-day Minnesota, perhaps ca. 1500.

In historic times they moev west, migrating across the Mississippi River and into North and South Dakota.

During the early nineteenth century, the Cheyenne form a unified tribe, with more centralized authority through ritual ceremonies and structure than other Plains tribes.

Having settled the Black Hills of South Dakota and the Powder River Country of present-day Montana, they introduce the horse culture to Lakota bands about 1730.

Allied with the Arapaho, they push the Kiowa to the South.

In turn they are pushed west by the more numerous Lakota.

In the centuries before European contact, the Cheyenne are at times allied with bands of the Lakota (Sioux) and Arapaho.

In the eighteenth century, they had migrated west away from Lakota warriors, but by the next century, bands of Lakota had followed them into the Black Hills and Powder River Country.

By the mid-nineteenth century, they are sometimes allied with other Plains tribes.

The Cheyenne are one of the best known of the Plains tribes.

The Cheyenne Nation forms into ten bands, spread across the Great Plains, from southern Colorado to the Black Hills in South Dakota.

At the same time, they create a centralized structure through ritual ceremonies, such as the Sun Dance.

When gathered, the bands leaders meet in formal council.

Alone among the Plains tribes, they wage war at the tribal level, first against their traditional enemy, the Crow, and later (1856–1879) against U.S. forces.

In the mid-nineteenth century, the bands begin to split, with some bands choosing to remain near the Black Hills, while others choose to remain near the Platte Rivers of central Colorado.

The Northern Cheyenne, known in Cheyenne either as Notameohmésêhese meaning "Northern Eaters" or simply as Ohmésêhese meaning "Eaters", live in southeast Montana on the Northern Cheyenne Indian Reservation.

In the 2000 census, the reservation had a total population of 4,400, with 72.8%, or about 3,250 people, identifying as Cheyenne.The Southern Cheyenne, known in Cheyenne as Heévâhetaneo'o meaning "Roped People", together with the Southern Arapaho, form the federally recognized tribe, the Cheyenne and Arapaho Tribes, situated in western Oklahoma.

Their combined population is 12,130, as of 2008.

In 2003, about eight thousand of these identified as Cheyenne.

With continued intermarriage, it is difficult to separate the tribes administratively.