Youngtown is a town in Maricopa County, Arizona, United States. According to the 2010 census, the population of the town is 6,156. Youngtown is the oldest retirement community in the US. In 1954, two developers bought 320 acres (1.3 km²) of farmland & built is notable as the first master-planned, adult community in the United States, dedicated exclusively to retirees, designed by Ben Schleifer. However, in 1996, the town denied extending the stay of a 16 year old child to live in the community. In response, the Arizona Attorney General investigated and determined it was unenforceable.