The Fort Belknap Indian Reservation is home to the Gros Ventre (Grovan) and the Assinboine tribes. The major city in the reservation is Hays, Montana, and the agency sits at the northern Border near Highway 2. Hays is a Census-designated place (CDP in Blaine County, Montana, United States. The following highways are numbered 2. For roads numbered A2, see A2.