Fairfield Township was formed by Royal charter on May 12, 1697, from portions of the Cohansey Township area, while still part of Salem County, and was formed as a precinct in the newly created Cumberland County on January 19, 1748. It was incorporated on February 21, 1798, as one of the initial group of 104 townships in the state by an act of the New Jersey Legislature. Portions of the township were taken to form Downe Township (September 26, 1772), Millville Township (February 24, 1801) and Lawrence Township (February 17, 1885).[20]

The Borough of Somerdale was created on April 23, 1929, from portions of Clementon Township, one of seven municipalities created from the now-defunct township, and one of five new municipalities (including Hi-Nella Borough, Lindenwold Borough, Pine Hill Borough and Pine Valley Borough) created on that same date.[20]

Norwood was formed as a borough by an act of the New Jersey Legislature on March 14, 1905, from portions of Harrington Township.[21]

The area had been known as Smith’s Mill and was later called Butts Bridge (variously spelled as “Butt’s Bridge” and “Butts’ Bridge”), named for a family that owned the eponymous crossing of the Paulins Kill.[21]

Union Beach was formed as a borough by an act of the New Jersey Legislature on March 16, 1925, from portions of Raritan Township (now Hazlet), based on the results of a referendum held on April 16, 1925.[21] A 100-acre (40 ha) farm in the future borough was owned by the Poole family since the days of the American Revolutionary War. Following the development of the Central Railroad of New Jersey, the Poole Farm became the site of the Union Subdivision in 1908,[22] while an area that had been called East Point Beach Estates was renamed Union Beach by developer Charles Carr in 1920.[23]

Jamesburg was formed as a borough by an act of the New Jersey Legislature on March 19, 1887, when it was created from portions of Monroe Township, based on the results of a referendum held on March 15, 1887. Jamesburg’s incorporation was confirmed on April 15, 1915.[20]

What is now Rochelle Park was originally incorporated as Midland Township on March 7, 1871, from portions of New Barbadoes Township. Portions of the township were taken to form the boroughs of Delford (on March 8, 1894; now Oradell), Maywood (June 30, 1894), Riverside (also June 30, 1894; now River Edge) and Paramus (March 2, 1922). Rochelle Park was formed as a township by an act of the New Jersey Legislature on November 5, 1929, replacing Midland Township, based on the results of a referendum held on that same day that passed by a 503–69 margin.[20] The main impetus behind the change in name was to avoid confusion with the nearby community of Midland Park.[21] The township was named for the port city of La Rochelle, France.[22][23]

Mullica Township was incorporated as a township by an act of the New Jersey Legislature on March 13, 1838, from the western section of Galloway Township. Egg Harbor City was created from portions of the township on June 14, 1858, while the Town of Hammonton was created and split off on March 5, 1866.[19]

Berlin was incorporated as a township on April 11, 1910, from portions of Waterford Township. Portions of the township were taken on March 29, 1927, to form Berlin Borough, based on the results of a referendum held on April 26, 1927.[20] The township was named for the city of Berlin, Germany.[21]

The township has been one of the state’s highest-income communities. Based on data from the 2012–2016 American Community Survey (ACS), NJ.com ranked the township as having the fifth-highest income in the state, with a median household income of $173,473.[20] Based on data from the 2014–2018 ACS, the township residents had a median household income of $162,037, more than double the statewide median of $79,363.[21]