The three Levittowns were large housing developments built from the mid-1940s through the early 1960s by William J. Levitt and his construction company. Levitt invented a process to mass-produce homes by making each home exactly the same. The first Levittown was located in New York and consisted of 17,000 homes. The subsequent Levittowns were built in New Jersey and Pennsylvania. Levittowns were the forerunner of the suburb.