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.
According to the United States Census Bureau, the town has a total area of 41.5 square miles (107.4 km), of which 41.3 square miles (107.0 km) are land and 0.2 square miles (0.4 km), or 0.39%, are water.
The west town line is marked by West Canada Creek. Fairfield is north of the Mohawk River, but does not border it.
New York State Route 29, an east-west highway, crosses Fairfield. New York State Route 169 is a north-south highway in the western part of the town. New York State Route 170 is another north-south highway, but in the eastern part of Fairfield. New York State Route 170A is at the east town line.
As of the census of 2000, there were 1,607 people, 561 households, and 430 families residing in the town. The population density was 39.1 people per square mile (15.1/km²). There were 611 housing units at an average density of 14.9 per square mile (5.7/km²). The racial makeup of the town was 98.44% White, 0.37% African American, 0.19% Native American, and 1.00% from two or more races. Hispanic or Latino of any race were 0.25% of the population.
There were 561 households out of which 35.8% had children under the age of 18 living with them, 64.2% were married couples living together, 7.8% had a female householder with no husband present, and 23.2% were non-families. 19.1% of all households were made up of individuals and 7.7% had someone living alone who was 65 years of age or older. The average household size was 2.78 and the average family size was 3.17.
In the town, the population was spread out with 26.3% under the age of 18, 7.0% from 18 to 24, 27.1% from 25 to 44, 25.8% from 45 to 64, and 13.8% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 103.2 males. For every 100 females age 18 and over, there were 96.0 males.
The median income for a household in the town was $40,104, and the median income for a family was $45,069. Males had a median income of $31,992 versus $21,944 for females. The per capita income for the town was $15,603. About 9.0% of families and 11.6% of the population were below the poverty line, including 13.7% of those under age 18 and 13.0% of those age 65 or over.