Plainfield is a city in Union County, New Jersey, United States. As of the 2010 United States Census, the city's population increased to 49,808, the highest ever recorded population in any decennial census, with the population having increased by 1,979 (+4.1%) from the 47,829 counted in the 2000 Census, which had in turn increased by 1,262 (+2.7%) from the 46,567 counted in the 1990 Census. Plainfield is nicknamed "The Queen City".
Plainfield was originally formed as a township on April 5, 1847, from portions of Westfield Township, while the area was still part of Essex County. On March 19, 1857, it became part of the newly created Union County. Plainfield was incorporated as a city by an Act of the New Jersey Legislature on April 21, 1869, from portions of Plainfield Township, based on the results of a referendum held that same day. The city and township coexisted until March 6, 1878, when Plainfield Township was dissolved and parts were absorbed by Plainfield city, with the remainder becoming Fanwood Township (now known as Scotch Plains).
It was settled in 1684 by Quakers, and incorporated as a city in 1869. Formerly a bedroom suburb in the New York metropolitan area, it has become the urban center of 10 closely allied municipalities, with diversified industries, including printing and the manufacture of chemicals, clothing, electronic equipment, and vehicular parts. Among the several 18th-century buildings remaining are a Friends' meetinghouse (1788), the Martine house (1717), and the Nathaniel Drake House (1746), known as George Washington's headquarters. Nearby Washington Rock is a prominent point of the Watchung Mountains and is reputed to be the vantage point from which Washington watched British troop movements.
In music history, Plainfield is known as the birthplace of P-Funk. George Clinton founded The Parliaments while working in a barber shop in Plainfield. Parliament-Funkadelic was inducted in the Rock and Roll Hall of Fame in 1997. Plainfield is now home to former New Jersey governor James McGreevey.
In sports history, Plainfield is the birthplace of several current and former athletes, including professionals and well-known amateurs. Included in their number are Milt Campbell, the 1956 Olympic Decathlon gold medalist (the first African-American to earn this title); and Joe Black, the first African-American pitcher to win a World Series game.
There are numerous sites, including homes, parks, and districts in town listed on the National Register of Historic Places.
Plainfield was affected by the Plainfield riots in July 1967. This civil disturbance occurred in the wake of the larger Newark riots. One Plainfield police officer died, about fifty people were injured, and several hundred thousand dollars of property was damaged by looting and arson. The New Jersey National Guard restored order after three days of unrest. This civil unrest caused a massive white flight, characterized by the percentage of black residents rising from 40% in 1970 to 60% a decade later.