The Gros Ventre, also known as the A'aninin, Atsina, or White Clay, are a historically Algonquian-speaking Native American tribe located in northcentral Montana. Today, the Gros Ventre people are enrolled in the Fort Belknap Indian Community of the Fort Belknap Reservation of Montana, a federally recognized tribe with 7,000 members, also including the Assiniboine people.