South Plainfield is a borough in northern Middlesex County, in the U.S. state of New Jersey. South Plainfield was incorporated as a borough on March 6, 1926, from portions of Piscataway Township.The borough is situated on the border with Union County in the Raritan Valley region, within the New York metropolitan area. As of the 2020 United States census, the borough's population was 24,338, its highest decennial count ever and an increase of 953 (+4.1%) from the 23,385 recorded at the 2010 census, which in turn reflected an increase of 1,575 (+7.2%) from the 21,810 counted in the 2000 census.Table 7. Population for the Counties and Municipalities in New Jersey: 1990, 2000 and 2010, New Jersey Department of Labor and Workforce Development, February 2011. Accessed May 1, 2023.

South Plainfield was incorporated by an act of the New Jersey Legislature on March 12, 1926, from portions of Piscataway, based on the results of a referendum passed on April 6, 1926.Snyder, John P. The Story of New Jersey's Civil Boundaries: 1606-1968, Bureau of Geology and Topography; Trenton, New Jersey; 1969. p. 174. Accessed May 30, 2024. The borough's name derives from Plainfield, which derived its name from a local estateHutchinson, Viola L. The Origin of New Jersey Place Names, New Jersey Public Library Commission, May 1945. Accessed August 9, 2026. or from its scenic location.Gannett, Henry. The Origin of Certain Place Names in the United States, p. 22. United States Government Printing Office, 1905. Accessed October 7, 2015.

Geography According to the United States Census Bureau, the borough had a total area of 8.33 square miles (21.58 km2), including 8.30 square miles (21.49 km2) of land and 0.04 square miles (0.09 km2) of water (0.42%).

Unincorporated communities, localities and place names located partially or completely within the township include Avon Park, Hadley Airport, Holly Park and Samptown.Locality Search, State of New Jersey. Accessed May 21, 2015.

The borough is bordered by Piscataway on the south and west, Edison on the east, both in Middlesex County, and by Plainfield on the north and Scotch Plains both in Union County.Areas touching South Plainfield, MapIt. Accessed March 8, 2020.Municipalities, Middlesex County, New Jersey. Accessed December 1, 2019.New Jersey Municipal Boundaries, New Jersey Department of Transportation. Accessed November 15, 2019.

Demographics

2020 census As of the 2020 census, South Plainfield had a population of 24,338. The median age was 40.7 years. 20.6% of residents were under the age of 18 and 16.8% of residents were 65 years of age or older. For every 100 females there were 95.0 males, and for every 100 females age 18 and over there were 93.1 males age 18 and over.

100.0% of residents lived in urban areas, while 0.0% lived in rural areas.

There were 8,217 households in South Plainfield, of which 36.0% had children under the age of 18 living in them. Of all households, 60.2% were married-couple households, 13.1% were households with a male householder and no spouse or partner present, and 21.8% were households with a female householder and no spouse or partner present. About 17.3% of all households were made up of individuals and 8.4% had someone living alone who was 65 years of age or older.

There were 8,432 housing units, of which 2.5% were vacant. The homeowner vacancy rate was 0.8% and the rental vacancy rate was 3.3%.

+ Racial composition as of the 2020 census Race Number Percent White 12,350 50.7% Black or African American 2,650 10.9% American Indian and Alaska Native 128 0.5% Asian 4,610 18.9% Native Hawaiian and Other Pacific Islander 6 0.0% Some other race 2,166 8.9% Two or more races 2,428 10.0% Hispanic or Latino (of any race) 4,555 18.7%

2010 census The 2010 United States census counted 23,385 people, 7,876 households, and 6,175 families in the borough. The population density was 2,808.5 per square mile (1,084.4/km2). There were 8,093 housing units at an average density of 971.9 per square mile (375.3/km2). The racial makeup was 66.74% (15,607) White, 10.10% (2,361) Black or African American, 0.37% (87) Native American, 14.68% (3,433) Asian, 0.03% (8) Pacific Islander, 4.79% (1,120) from other races, and 3.29% (769) from two or more races. Hispanic or Latino of any race were 13.24% (3,097) of the population.

Of the 7,876 households, 35.2% had children under the age of 18; 62.1% were married couples living together; 12.3% had a female householder with no husband present and 21.6% were non-families. Of all households, 18.2% were made up of individuals and 8.2% had someone living alone who was 65 years of age or older. The average household size was 2.93 and the average family size was 3.34.

23.0% of the population were under the age of 18, 8.0% from 18 to 24, 26.2% from 25 to 44, 29.2% from 45 to 64, and 13.5% who were 65 years of age or older. The median age was 40.2 years. For every 100 females, the population had 94.4 males. For every 100 females ages 18 and older there were 92.1 males.

The Census Bureau's 2006–2010 American Community Survey showed that (in 2010 inflation-adjusted dollars) median household income was $92,263 (with a margin of error of +/− $5,066) and the median family income was $98,913 (+/− $4,289). Males had a median income of $61,480 (+/− $7,597) versus $48,639 (+/− $4,924) for females. The per capita income for the borough was $33,495 (+/− $1,546). About 2.7% of families and 4.0% of the population were below the poverty line, including 3.9% of those under age 18 and 2.5% of those age 65 or over.DP03: Selected Economic Characteristics from the 2006-2010 American Community Survey 5-Year Estimates for South Plainfield borough, Middlesex County, New Jersey , United States Census Bureau. Accessed August 28, 2012.

2000 census As of the 2000 United States census there were 21,810 people, 7,151 households, and 5,856 families residing in the borough. The population density was . There were 7,307 housing units at an average density of . The racial makeup of the borough was 77.74% White, 8.56% African American, 0.22% Native American, 7.57% Asian, 3.48% from other races, and 2.42% from two or more races. Hispanic or Latino of any race were 8.66% of the population.Census 2000 Profiles of Demographic / Social / Economic / Housing Characteristics for South Plainfield borough, New Jersey , United States Census Bureau. Accessed August 28, 2012.DP-1: Profile of General Demographic Characteristics: 2000 - Census 2000 Summary File 1 (SF 1) 100-Percent Data for South Plainfield borough, Middlesex County, New Jersey , United States Census Bureau. Accessed August 28, 2012.

There were 7,151 households, out of which 37.6% had children under the age of 18 living with them, 66.8% were married couples living together, 10.9% had a female householder with no husband present, and 18.1% were non-families. 15.3% of all households were made up of individuals, and 7.5% had someone living alone who was 65 years of age or older. The average household size was 3.01 and the average family size was 3.35.

In the borough, the population was spread out, with 25.1% under the age of 18, 7.2% from 18 to 24, 29.9% from 25 to 44, 23.7% from 45 to 64, and 14.1% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 96.1 males. For every 100 females age 18 and over, there were 92.6 males.

The median income for a household in the borough was $67,466, and the median income for a family was $72,745. Males had a median income of $47,465 versus $34,329 for females. The per capita income for the borough was $25,270. About 2.3% of families and 3.4% of the population were below the poverty line, including 3.7% of those under age 18 and 4.4% of those age 65 or over. Economy Tumi Inc. is a manufacturer of suitcases and bags for travel that was founded in 1975 by Charlie Clifford after serving in Peru with the Peace Corps.Corporate Contacts, Tumi Inc. Accessed October 7, 2015.

PTC Therapeutics is a pharmaceutical company focused on the development of small molecule, orally administered treatments for orphan diseases.Locations, PTC Therapeutics. Accessed October 7, 2015.

Jem Records (also known as JEM Records) was a record label that existed from 1970 to 1988, at the time principally known as the parent company of Passport Records; The label was resurrected in 2013 as Jem Recordings.Siler, Julia Flynn. "Business People; Jem Records President Confident Despite Woes", The New York Times, August 22, 1988. Accessed October 7, 2015. "For two decades, Martin L. Scott, the 38-year-old president and co-founder of Jem Records Inc., has tied his fortunes to those of the pioneering independent record company.... As a result, the future of the South Plainfield, N.J., company and Mr. Scott in the industry is unclear, but in an interview he expressed confidence in the company's restructuring plan and his own future."

Sports The Plainfield Curling Club is a curling club that owns and operates the only dedicated curling facility in New Jersey. Established in 1963, the club's two-sheet structure was completed in 1967.About, Plainfield Curling Club. Accessed March 8, 2020. "The Plainfield Curling Club (PCC) was founded in 1963 and is the only curling club active with its own indoor ice facility in New Jersey."

Government

Local government South Plainfield is governed under the borough form of New Jersey municipal government, which is used in 218 municipalities (of the 564) statewide, making it the most common form of government in New Jersey.Inventory of Municipal Forms of Government in New Jersey, Rutgers University Center for Government Studies, July 1, 2011. Accessed June 1, 2023. The governing body is composed of the mayor and the borough council, with all positions elected at-large on a partisan basis as part of the November general election. The mayor is elected directly by the voters to a four-year term of office. The borough council includes six members elected to serve three-year terms on a staggered basis, with two seats coming up for election each year in a three-year cycle.2012 New Jersey Legislative District Data Book, Rutgers University Edward J. Bloustein School of Planning and Public Policy, March 2013, p. 84. The borough form of government used by South Plainfield is a "weak mayor / strong council" government in which council members act as the legislative body with the mayor presiding at meetings and voting only in the event of a tie. The mayor can veto ordinances subject to an override by a two-thirds majority vote of the council. The mayor makes committee and liaison assignments for council members, and most appointments are made by the mayor with the advice and consent of the council.Cerra, Michael F. "Forms of Government: Everything You've Always Wanted to Know, But Were Afraid to Ask" , New Jersey State League of Municipalities. Accessed November 30, 2014."Forms of Municipal Government in New Jersey", p. 6. Rutgers University Center for Government Studies. Accessed June 1, 2023.