Trenton is the capital city of the U.S. state of New Jersey and the county seat of Mercer County. It was briefly the capital of the United States. The city's metropolitan area is grouped with the New York metropolitan area by the United States Census Bureau, but directly borders the Philadelphia metropolitan area and is part of the Federal Communications Commission's Philadelphia Designated Market Area. As of the 2010 United States Census, Trenton had a population of 84,913, making it the state's 10th-most-populous municipality. The Census Bureau estimated that the city's population was 84,034 in 2014.