Fairfield is a town in Teton County, Montana, United States. The population was 659 at the 2000 census. Fairfield is the self-proclaimed "Malting Barley Capital of the World" with 83,000 acres (336 km2) of irrigated cropland and 56,000 acres (227 km2) of non-irrigated cropland in production for the purpose of raising malt barley in the vicinity.
Fairfield is located at 47°36′55″N 111°58′51″W / 47.61528°N 111.98083°W / 47.61528; -111.98083 (47.615250, -111.980859).
According to the United States Census Bureau, the town has a total area of 0.3 square miles (0.8 km²), all of it land.