Islip ( EYE-slip) is one of ten towns in Suffolk County, New York (USA). Located on the South Shore of Long Island, the town population was 335,543 at the 2010 census. Within the Town of Islip is a smaller, unincorporated hamlet and census-designated place also named Islip.
At the 2000 census, there were 322,612 people, 98,936 households and 78,555 families residing in the town. The population density was 3,064.5 per square mile (1,183.1/km²). There were 104,278 housing units at an average density of 990.5 per square mile (382.4/km²). The racial makeup of the town was 77.25% White, 9.02% Black or African American, 0.26% Native American, 2.17% Asian, 0.05% Pacific Islander, 8.32% from other races, and 2.93% from two or more races. Hispanic or Latino of any race were 20.16% of the population.
There were 98,936 households of which 39.4% had children under the age of 18 living with them, 62.4% were married couples living together, 12.3% had a female householder with no husband present, and 20.6% were non-families. 16.2% of all households were made up of individuals and 6.4% had someone living alone who was 65 years of age or older.