Trenton is the capital of the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of New Jersey

New Jersey

New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

 and the county seat

County seat

A county seat is an administrative center, or seat of government, for a county or civil parish. The term is primarily used in the United States....

 of Mercer County

Mercer County, New Jersey

As of the census of 2000, there were 350,761 people, 125,807 households, and 86,303 families residing in the county. The population density was 1,552 people per square mile . There were 133,280 housing units at an average density of 590 per square mile...

. As of the 2010 United States Census, Trenton had a population of 84,913. The city is part of the Greater New York City Combined Statistical Area.
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

Hunterdon County, New Jersey

Hunterdon County is a county located in the western section of the U.S. state of New Jersey. As of the 2010 United States Census, the population was 128,349. It is part of the New York Metropolitan Area. Its county seat is Flemington....

. 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.