South Amboy is a city in Middlesex County, New Jersey, on the Raritan Bay. As of the United States 2000 Census, the city population was 7,913. South Amboy, and Perth Amboy across the Raritan River, are collectively referred to as The Amboys. Signage for Exit 11 on the New Jersey Turnpike refers to "The Amboys" as a destination. South Amboy has passed through three of the five types of New Jersey municipalities. It was first mentioned on 28 May 1782 in Freeholder minutes as being formed from Perth Amboy Township, and then formally incorporated as a township on 21 February 1798. Over the next 90 years, portions broke away to form Monroe Township (9 April 1838), Madison Township (2 March 1869; later Old Bridge Township) and Sayreville Township (6 April 1876; later Borough of Sayreville). As of 25 February 1888, South Amboy borough was formed, replacing South Amboy Township. On 11 April 1908, South Amboy was incorporated as a city, replacing South Amboy borough, with a referendum held on 21 July 1908.