Andover is a town in Allegany County, New York, United States. The population was 1,830 at the 2010 census. The town is on the eastern edge of Allegany County and contains the village of Andover.
According to the United States Census Bureau, the town has a total area of 39.5 square miles (102.3 km), of which 39.4 square miles (102.1 km) is land and 0.077 square miles (0.2 km), or 0.17%, is water.
The east town line is the border of Steuben County.
New York State Route 21 ends at New York State Route 417 at Andover village.
As of the census of 2000, there were 1,945 people, 742 households, and 517 families residing in the town. The population density was 49.3 people per square mile (19.0/km²). There were 877 housing units at an average density of 22.2 per square mile (8.6/km²). The racial makeup of the town was 97.89% White, 0.15% Black or African American, 0.10% Native American, 0.51% Asian, 0.46% from other races, and 0.87% from two or more races. Hispanic or Latino of any race were 1.13% of the population.
There were 742 households out of which 34.0% had children under the age of 18 living with them, 58.0% were married couples living together, 7.5% had a female householder with no husband present, and 30.2% were non-families. 24.9% of all households were made up of individuals and 12.0% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.13.
In the town, the population was spread out with 27.8% under the age of 18, 9.1% from 18 to 24, 25.5% from 25 to 44, 23.5% from 45 to 64, and 14.1% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 93.9 males. For every 100 females age 18 and over, there were 93.3 males.
The median income for a household in the town was $34,107, and the median income for a family was $40,341. Males had a median income of $30,742 versus $21,012 for females. The per capita income for the town was $19,273. About 7.2% of families and 10.4% of the population were below the poverty line, including 13.3% of those under age 18 and 3.6% of those age 65 or over.