Philadelphia (/ˌfɪləˈdɛlfiə/) is the largest city in the Commonwealth of Pennsylvania and the sixth-most populous city in the United States, with an estimated population of 1,567,872 and more than 6 million in the seventh-largest metropolitan statistical area, as of 2016. Philadelphia is the economic and cultural anchor of the Delaware Valley, located along the lower Delaware and Schuylkill Rivers, within both the Mid-Atlantic region and the Northeast megalopolis. The Delaware Valley's population of 7.2 million ranks it as the eighth-largest combined statistical area in the United States.
William Penn, an English Quaker, founded the city in 1682 to serve as capital of the Pennsylvania Colony. Philadelphia played an instrumental role in the American Revolution as a meeting place for the Founding Fathers of the United States, who signed the Declaration of Independence in 1776 at the Second Continental Congress, and the Constitution at the Philadelphia Convention of 1787. Several other key events occurred in Philadelphia during the Revolutionary War including the First Continental Congress, the preservation of the Liberty Bell, the Battle of Germantown, and the Siege of Fort Mifflin. Philadelphia was one of the nation's capitals during the revolution, and served as temporary U.S. capital while Washington, D.C., was under construction. In the 19th century, Philadelphia became a major industrial center and a railroad hub. The city grew from an influx of European immigrants, most of whom came from Ireland, Italy and Germany—the three largest reported ancestry groups in the city as of 2015. In the early 20th century, Philadelphia became a prime destination for African Americans during the Great Migration after the Civil War, as well as Puerto Ricans. The city's population doubled from one million to two million people between 1890 and 1950.
In 1681, in partial repayment of a debt, Charles II of England granted Penn a charter for what would become the Pennsylvania colony. Despite the royal charter, Penn bought the land from the local Lenape to be on good terms with the Native Americans and ensure peace for his colony. Penn made a treaty of friendship with Lenape chief Tammany under an elm tree at Shackamaxon, in what is now the city's Fishtown neighborhood. Penn named the city Philadelphia, which is Greek for brotherly love (from philos, "love" or "friendship", and adelphos, "brother"). As a Quaker, Penn had experienced religious persecution and wanted his colony to be a place where anyone could worship freely. This tolerance, far more than afforded by most other colonies, led to better relations with the local native tribes and fostered Philadelphia's rapid growth into America's most important city.
Philadelphia's neighborhoods are divided into large sections—North, Northeast, South, Southwest Philadelphia, West, and Northwest—surrounding Center City, which corresponds closely with the city's limits before consolidation in 1854. Each of these large areas contains numerous neighborhoods, some of whose boundaries derive from the boroughs, townships, and other communities that constituted Philadelphia County before their inclusion within the city.
The City Planning Commission, tasked with guiding growth and development of the city, has divided the city into 18 planning districts as part of the Philadelphia2035 physical development plan. Much of the city's 1980 zoning code was overhauled from 2007 to 2012 as part of a joint effort between former mayors John F. Street and Michael Nutter. The zoning changes were intended to rectify incorrect zoning maps in order to facilitate future community development, as the city forecasts an additional 100,000 residents and 40,000 jobs will be added by 2035.
According to a 2014 study by the Pew Research Center, 68% of the population of the city identified themselves as Christian, with 41% professing attendance at a variety of churches that could be considered Protestant, 26% professing Catholic beliefs, and less than 1% are Mormons, while the remaining 24% claim no religious affiliation. The same study says that other religions collectively compose about 8% of the population, including Judaism, Buddhism, Islam, and Hinduism.
The Philadelphia metropolitan area's Jewish population was estimated at 206,000 in 2001, which was the sixth largest in the United States at that time.
Other religious groups in Philadelphia include Buddhism in Chinatown, and Caribbean and traditional African religions in North and West Philadelphia. Historically, the city has strong connections to the Quakers, Unitarian Universalism, and the Ethical Culture movement, all of which continue to be represented in the city. The Quaker Friends General Conference is based in Philadelphia.
African diasporic religions are practiced in some Hispanic and Caribbean communities in North and West Philadelphia.
Like many American cities, Philadelphia saw a gradual yet pronounced rise in crime in the years following World War II. There were 525 murders in 1990, a rate of 31.5 per 100,000. There were an average of about 600 murders a year for most of the 1990s. The murder count dropped in 2002 to 288, then rose four years later to 406 in 2006 and 392 in 2007. A few years later, Philadelphia began to see a rapid drop in homicides and violent crime. In 2013, there were 246 murders, which is a decrease of over 25% from the previous year, and a decrease of over 44% since 2007. And in 2014, there were 248 homicides, up by one since 2013. In 2015, according to annual homicide statistics and crime maps provided on the Philadelphia Police Department's website, there were 280 murders in the city. The same departmental site documents that the number of homicides fell slightly (1.07%) the following year, with 277 murders in Philadelphia in 2016.
Two airports serve Philadelphia: the Philadelphia International Airport (PHL) is located 7 mi (11 km) south-southwest of Center City on the boundary with Delaware County, providing scheduled domestic and international air service, while Northeast Philadelphia Airport (PNE) is a general aviation relief airport in Northeast Philadelphia serving general and corporate aviation. Philadelphia International Airport is among the busiest airports in the world measured by traffic movements (i.e., takeoffs and landings). More than 30 million passengers pass through the airport annually on 25 airlines, including all major domestic carriers. The airport has nearly 500 daily departures to more than 120 destinations worldwide. SEPTA's Airport Regional Rail Line provides direct service between Center City railroad stations and Philadelphia International Airport.