Wilmington is a town in Essex County, New York, United States. The population was 1,253 at the 2010 census. The town is named after Wilmington, Vermont.
According to the United States Census Bureau, the town has a total area of 65.3 square miles (169.0 km), of which 65.3 square miles (169.0 km) is land and 0.2 square miles (0.6 km), or 0.36%, is water.
The north town line is the border of Clinton County. At the northwest corner is the corresponding corner of Franklin County.
The West Branch of the Ausable River flows northeastward through the center of the town.
New York State Route 431, an east–west highway known as Whiteface Mountain Memorial Highway, intersects New York State Route 86, a north–south highway in Wilmington village.
At the 2000 census, there were 1,131 people, 460 households and 304 families residing in the town. The population density was 17.4 people per square mile (6.7/km²). There were 734 housing units at an average density of 11.3 per square mile (4.3/km²). The racial makeup of the town was 98.59% White, 0.09% African American, 0.35% Native American, 0.09% Asian, 0.18% from other races, and 0.71% from two or more races. Hispanic or Latino of any race were 0.62% of the population.
There were 460 households of which 35.0% had children under the age of 18 living with them, 53.0% were married couples living together, 8.7% had a female householder with no husband present, and 33.7% were non-families. 27.4% of all households were made up of individuals and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 3.01.
27.7% of the population were under the age of 18, 5.9% from 18 to 24, 29.2% from 25 to 44, 23.7% from 45 to 64, and 13.5% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 97.0 males. For every 100 females age 18 and over, there were 96.6 males.
The median household income was $34,432 and the median family income was $43,077. Males had a median income of $27,604 and females $21,328. The per capita income was $18,052. About 6.6% of families and 10.0% of the population were below the poverty line, including 11.3% of those under age 18 and 4.7% of those age 65 or over.