Hays is a census-designated place in Blaine County, Montana, United States. The population was 843 at the 2010 census. The community lies within the Fort Belknap Indian Reservation, near the reservation's southern end. The nearby community of Lodge Pole lies to the east. The town was named for Major Hays. The Bureau of Catholic Indian Missions built St. Paul's Mission Church at Hays in 1887.