The Arapaho (; in French: Arapahos, Gens de Vache) are a tribe of Native Americans historically living on the plains of Colorado and Wyoming. They were close allies of the Cheyenne tribe and loosely aligned with the Lakota and Dakota. The Arapaho language, Heenetiit, is an Algonquian language closely related to Gros Ventre (Ahe/A'ananin), whose people are considered to have separated from the Arapaho at an early time. The Blackfeet and Cheyenne also speak Algonquian languages, but theirs are quite different from Arapaho.
Around 3,000 years ago, the ancestral Arapaho-speaking people (Heeteinono'eino' ) lived in the western Great Lakes region along the Red River Valley in what is classified as present-day Manitoba, Canada and Minnesota, United States. There the Arapaho were an agricultural people who grew crops, including maize. Following European colonization in eastern Canada, together with the early Cheyenne people (Hitesiino'), the Arapaho were pushed westward onto the eastern Great Plains by the Ojibwe. They were numerous and powerful, having obtained guns from their French trading allies. The ancestors of the Arapaho people entered the Great Plains from the western Great Lakes region sometime before 1700. During their early history on the plains, the Arapaho lived on the northern plains from the South Saskatchewan River in Canada south to Montana, Wyoming, and western South Dakota. Before the Arapaho acquired horses, they used domestic dogs as pack animals to pull their travois. The Arapaho acquired horses in the early 1700s from other tribes, which changed their way of life. They became a nomadic people, using the horses as pack and riding animals. They could transport greater loads, and travel more easily by horseback to hunt more easily and widely, increasing their success in hunting on the Plains. Gradually, the Arapaho moved farther south, split into the closely allied Northern and Southern Arapaho, and established a large joint territory spanning land in southern Montana, most of Wyoming, the Nebraska Panhandle, central and eastern Colorado, western Oklahoma, and extreme western Kansas. A large group of Arapaho split from the main tribe and became an independent people, commonly known as the Gros Ventre (as named by the French) or Atsina. The name Gros Ventre, meaning "Big Bellies" in French, was a misinterpretation of sign language between an Indian guide and French explorers. The Gros Ventre spoke an Algonquian language similar to Arapaho after the division; they identified as A'aninin meaning ''White Clay people''. The Arapaho often viewed the Gros Ventre as inferior and referred to them as Hitunena or Hitouuteen, meaning "beggars".

Q: What was the earliest record of the Arapaho?
A: Around 3,000 years ago, the ancestral Arapaho-speaking people (Heeteinono'eino' ) lived in the western Great Lakes region along the Red River Valley

Q: Who was the chief of the tribe?
A: unknown
How many Arapaho were there?
unknown unknown unknown unknown unknown
unknown