North Castle is a town in Westchester County, New York, United States. The population was 11,841 at the 2010 census. It has no villages.
As of the census of 2000, there were 10,849 people, 3,583 households, and 3,002 families residing in the town. The population density was 450.4 people per square mile (173.9/km²). There were 3,706 housing units at an average density of 153.9 per square mile (59.4/km²). The racial makeup of the town was 92.38% White, 1.76% African American, 0.03% Native American, 3.96% Asian, 0.05% Pacific Islander, 0.63% from other races, and 1.20% from two or more races. Hispanic or Latino of any race were 4.14% of the population.
There were 3,583 households out of which 44.2% had children under the age of 18 living with them, 74.6% were married couples living together, 6.9% had a female householder with no husband present, and 16.2% were non-families. 13.1% of all households were made up of individuals and 5.5% had someone living alone who was 65 years of age or older. The average household size was 2.99 and the average family size was 3.28.
In the town the population was spread out with 29.7% under the age of 18, 4.5% from 18 to 24, 26.8% from 25 to 44, 28.3% from 45 to 64, and 10.7% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 97.1 males. For every 100 females age 18 and over, there were 94.7 males.
The median income for a household in the town was $117,815, and the median income for a family was $141,764. Males had a median income of $86,950 versus $49,500 for females. The per capita income for the town was $60,628. About 1.0% of families and 3.0% of the population were below the poverty line, including 1.7% of those under age 18 and 3.4% of those age 65 or over.