Trenton is the capital city of the U.S. state of New Jersey and the county seat of Mercer County. It briefly served as the capital of the United States in 1784. The city's metropolitan area, consisting of Mercer County, is grouped with the New York Combined Statistical Area by the United States Census Bureau, but it directly borders the Philadelphia metropolitan area and was from 1990 until 2000 part of the Philadelphia Combined Statistical Area. As of the 2010 United States Census, Trenton had a population of 84,913, making it the state's tenth-most-populous municipality. The Census Bureau estimated that the city's population was 83,974 in 2018.
Trenton dates back at least to June 3, 1719, when mention was made of a constable being appointed for Trenton while the area was still part of Hunterdon County. Boundaries were recorded for Trenton Township as of March 2, 1720. a courthouse and jail were constructed in Trenton around 1720, and the Freeholders of Hunterdon County met annually in Trenton. Trenton became New Jersey's capital as of November 25, 1790, and the City of Trenton was formed within Trenton Township on November 13, 1792. Trenton Township was incorporated as one of New Jersey's initial group of 104 townships by an act of the New Jersey Legislature on February 21, 1798. On February 22, 1834, portions of Trenton Township were taken to form Ewing Township.