Fairfield is a town in Herkimer County, New York, United States. The population was 1,627 at the 2010 census. The town is named after Fairfield, Connecticut.
The town is north of the village of Herkimer and east of Utica. The hamlet of Fairfield is in the central part of the town.
A few settlers, actually tenants, made the future town their home before the American Revolution, but the major influx took place after 1785, mainly from New England.
The town was established from part of the town of Norway in 1796.
From 1802 to 1901, the Fairfield Academy offered secondary and higher education at its campus in the hamlet of Fairfield. From 1812 until 1841, the Fairfield Medical College, a division of the academy, trained medical practitioners, including Marcus Whitman.
According to the United States Census Bureau, the town has a total area of , of which are land and , or 0.39%, are water.
The western town line is marked