The Homestead Farm at Oak Ridge was the site of a skirmish preceding the Battle of Short Hills.

Clark was incorporated as a township by an act of the New Jersey Legislature on March 23, 1864, from portions of Rahway.

[29] In March 2022, NJ Advance Media, a local newspaper, revealed a recording of Mayor Sal Bonaccorso using racial slurs when talking to members of the police department, despite him having previously denied doing so, and also saying women police officers were "disasters".

The newspaper also reported that in January 2020, Clark Township had paid Clark police lieutenant Antonio Manata $400,000 to not reveal racist and sexist comments made by the Mayor and Chief of Police and to turn over the tapes he had recorded.

[30][31][32] The New Jersey Office of Public Integrity and Accountability subsequently took control of the Union County investigation.

[2][3] Unincorporated communities, localities and place names located partially or completely within the township include Ashbrook, Florence Mills, Lenox, Madison Hill and Picton.

[35][36][37] An abandoned rail spur, the Bloodgood Branch of the Lehigh Valley Railroad, runs through Clark.

[citation needed] The 2010 United States census counted 14,756 people, 5,562 households, and 4,038 families in the township.

[47] According to the 2009–2013 American Community Survey, the largest ancestry groups were:[48] As of the 2000 United States census[15] there were 14,597 people, 5,637 households, and 4,126 families residing in the township.

[49] The Clark Township Committee is comprised of seven members, who are all chosen on a partisan basis in even-numbered years as part of the November general election.

[52][4][53][54][55][56][57] In January 2025, Mayor Sal Bonaccorso, who had just been re-elected for his seventh term, pleaded guilty to charges of criminal misconduct and was required to step down from office; Council President Angel Albanese will serve on an interim basis until a permanent replacement is chosen to fill the balance of the term of office.

[60][61][62] For the 119th United States Congress, New Jersey's 7th congressional district is represented by Thomas Kean Jr. (R, Westfield).

[64] For the 2024-2025 session, the 22nd legislative district of the New Jersey Legislature is represented in the State Senate by Nicholas Scutari (D, Linden) and in the General Assembly by Linda S. Carter (D, Plainfield) and James J. Kennedy (D, Rahway).

[66] As of 2025[update], Union County's County Commissioners are: Rebecca Williams (D, Plainfield, 2025),[67] Joesph Bodek (D, Linden, 2026),[68] James E. Baker Jr. (D, Rahway, 2027),[69] Michele Delisfort (D, Union Township, 2026),[70] Sergio Granados (D, Elizabeth, 2025),[71] Bette Jane Kowalski (D, Cranford, 2025),[72] Vice Chair Lourdes M. Leon (D, Elizabeth, 2026),[73] Alexander Mirabella (D, Fanwood, 2027)[74] and Chair Kimberly Palmieri-Mouded (D, Westfield, 2027).

[75][76] Constitutional officers elected on a countywide basis are: Clerk Joanne Rajoppi (D, Union Township, 2025),[77][78] Sheriff Peter Corvelli (D, Kenilworth, 2026)[79][80] and Surrogate Christopher E. Hudak (D, Clark, 2027).

[86] Among the township's 2010 Census population, 69.1% (vs. 53.3% in Union County) were registered to vote, including 87.6% of those ages 18 and over (vs. 70.6% countywide).

[116] The Lehigh Valley Railroad served Clark with a passenger station in the Picton section.

[117] The rail line remains active under Conrail's auspices, excluding the Bloodgood Branch spur which is now out of service.

The closest NJ Transit rail station is in Rahway, located approximately 2 miles (3.2 km) from the center of Clark.

The 112 route provides service to the Port Authority Bus Terminal in Midtown Manhattan,[118] as well as stops throughout downtown Elizabeth.