Iselin /ˈɪzɛlɪn/ is an unincorporated community and census-designated place located within Woodbridge Township, in Middlesex County, New Jersey, United States. As of the 2010 United States Census, the CDP's population was 18,695.Previously known as Perrytown and Unionville, Iselin received its current name after a New York investment banker and philanthropist Adrian Georg Iselin in the 1870s. He established a finishing school for girls from wealthy New York families there and subsidized the erection of a new train station which was replaced by a newer station to the south known as Metropark. The largest bordering town of Iselin is Edison.