Armonk is a hamlet and census-designated place (CDP) in the town of North Castle, New York located in Westchester County. As of the 2010 census, Armonk’s CDP population is 4,330 and it has a total area of 6.1 square miles (15.7 km), of which 6.0 square miles (15.5 km) is land and 0.077 square miles (0.2 km), or 1.54 percent, is water. Armonk is well known as being the headquarters of IBM.
As of the census of 2000, there were 3,461 people, 1,172 households, and 995 families residing in the CDP. The population density is 568.9 per square mile (219.8/km²). There are 1,204 housing units at an average density of 197.9/sq mi (76.5/km²). The racial makeup of the CDP is 93.38 percent white, 0.61 percent African American, 0.06 percent Native American, 4.16 percent Asian, 0.00 percent Pacific Islander, 0.40 percent from other races, and 1.24 percent from two or more races. 3.76 percent of the population are Hispanic and Latino Americans.
There are 1,172 households out of which 44.5 percent have children under the age of 18 living with them, 74.7 percent are married couples living together, 7.7 percent have a female householder with no husband present, and 15.1 percent are non-families. 13.1 percent of all households are made up of individuals and 6.0 percent have someone living alone who is 65 years of age or older. The average household size is 2.95 and the average family size is 3.23.
In the CDP, the population is spread out with 29.8 percent under the age of 18, 4.4 percent from 18 to 24, 27.2 percent from 25 to 44, 26.7 percent from 45 to 64, and 11.8 percent who are 65 years of age or older. The median age is 39 years. For every 100 females, there are 90.6 males. For every 100 females age 18 and over, there are 90.2 males.
As of the census of 2013, the median income for a household in the CDP is $159,530, and the median income for a family is $189,163. The per capita income for the CDP is $92,750. 1.3 percent of the population and 0.0 percent of families are below the poverty line. Out of the total population, 0.0 percent of those under the age of 18 and 3.9 percent of those 65 and older are living below the poverty line.