Philadelphia, Pennsylvania is the sixth-most-populous city in the United States and the largest in the Commonwealth of Pennsylvania, both in area and population. Since 1854, the city has been coterminous with Philadelphia County. Philadelphia has the second-largest downtown residential population in the US, after New York City. As of 2017[update], the Philadelphia metropolitan area is the eighth-largest in the US, with more than 6 million people. Philadelphia is the central city of the Delaware Valley metropolitan area.
Philadelphia is one of the oldest and most historically significant US cities. It was the nation's first capital. At the time of the American Revolution, it was the second-largest English-speaking city in the world, after only London. Into the first part of the 19th century, it was the country's most populous city and eclipsed Boston and New York City in political and social importance. Benjamin Franklin played an extraordinary role in Philadelphia's rise.