Fairfield is a town in Teton County, Montana, United States. The population was 759 at the 2020 census. Fairfield is the self-proclaimed "Malting Barley Capital of the World" due to their large crops each year of malt barley. Fairfield is a trade center for the farming community. Companies located there include Busch Agricultural Resources, 3 Rivers Telephone Cooperative and Sun River Electric Cooperative.