Philadelphia, known casually as Philly, is the largest city in the U.S. state of Pennsylvania, and the sixth-most populous U.S. city with a 2019 estimated population of 1,584,138.[Since 1854, the city has had the same geographic boundaries as Philadelphia County, the most populous county in Pennsylvania and the urban core of the eighth-largest U.S. metropolitan statistical area, with over 6 million residents as of 2017.Philadelphia is also the economic and cultural anchor of the greater Delaware Valley, located along the lower Delaware and Schuylkill Rivers, within 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.Philadelphia is one of the oldest municipalities 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 remained the nation's largest city until being overtaken by New York City in 1790; the city was also one of the nation's capitals during the revolution, serving as temporary U.S. capital while Washington, D.C. was under construction. The city's population doubled from one million to two million people between 1890 and 1950. The Philadelphia area's many universities and colleges make it a top study destination, as the city has evolved into an educational and economic hub.

As of 2019, the Philadelphia metropolitan area is estimated to produce a gross metropolitan product of $490 billion. Philadelphia is the center of economic activity in Pennsylvania and is home to five Fortune 1000 companies. The Philadelphia skyline is expanding, with a market of almost 81,900 commercial properties in 2016, including several nationally prominent skyscrapers. Philadelphia has more outdoor sculptures and murals than any other American city. The city is known for its arts, culture, cuisine, and colonial history, attracting 42 million domestic tourists in 2016 who spent $6.8 billion, generating an estimated $11 billion in total economic impact in the city and surrounding four counties of Pennsylvania. Philadelphia has also emerged as a biotechnology hub.Philadelphia is the birthplace of the United States Marine Corps,and is also the home of many U.S. firsts, including the first library , hospital , medical school , national capital , stock exchange , zoo , and business school . Philadelphia contains 67 National Historic Landmarks and the World Heritage Site of Independence Hall. The city became a member of the Organization of World Heritage Cities in 2015, as the first World Heritage City in the United States. Although Philadelphia is rapidly undergoing gentrification, the city actively maintains strategies to minimize displacement of homeowners in gentrifying neighborhoods.

Philadelphia has been described both as the elegant but rather jaded great lady and as the overage and sickly spinster of American cities.
 

• It is the 1st World Heritage City in the United States & 3rd most populous downtown in the country
• It boasts the 6th largest workforce in the U.S. of just over 3 million, including highly skilled talent in key industries
• The city is home to America's first zoo, the first hospital and the first medical school
• Philadelphia is actually renowned for its medical sector. One out of every six doctors in the U.S. is trained here
• Philly became home to the first general purpose computer in 1946, which weighed 27 tons
• Boasting over 2000 outdoor murals, it’s been called the “mural capital of the U.S.”
   

From a governmental perspective, Philadelphia County is a legal nullity, as all county functions were assumed by the city in 1952. The city has been coterminous with the county since 1854. Philadelphia's 1952 Home Rule Charter was written by the City Charter Commission, which was created by the Pennsylvania General Assembly in an act of April 21, 1949, and a city ordinance of June 15, 1949. The existing city council received a proposed draft on February 14, 1951, and the electors approved it in an election held April 17, 1951. The first elections under the new Home Rule Charter were held in November 1951, and the newly elected officials took office in January 1952. The city uses the strong-mayor version of the mayor–council form of government, which is led by one mayor in whom executive authority is vested. The mayor has the authority to appoint and dismiss members of all boards and commissions without the approval of the city council. Elected at-large, the mayor is limited to two consecutive four-year terms, but can run for the position again after an intervening term.

Philadelphia County is coterminous with the First Judicial District of Pennsylvania. The Philadelphia County Court of Common Pleas is the trial court of general jurisdiction for the city, hearing felony-level criminal cases and civil suits above the minimum jurisdictional limit of $10,000. The court also has appellate jurisdiction over rulings from the Municipal and Traffic Courts, and some administrative agencies and boards. The trial division has 70 commissioned judges elected by the voters, along with about one thousand other employees.The court also has a family division with 25 judges and an orphans' court with three judges.As of 2018, the city's District Attorney is Larry Krasner, a Democrat. The last Republican to hold the office is Ronald D. Castille, who left in 1991 and later served as the Chief Justice of the Pennsylvania Supreme Court from 2008 to 2014.The Philadelphia Municipal Court handles traffic cases, misdemeanor and felony criminal cases with maximum incarceration of five years, and civil cases involving $12,000 or less , and all landlord-tenant disputes. The municipal court has 27 judges elected by the voters.Pennsylvania's three appellate courts also have sittings in Philadelphia. The Supreme Court of Pennsylvania, the court of last resort in the state, regularly hears arguments in Philadelphia City Hall.

Philadelphia was a bastion of the Republican Party from the American Civil War until the mid-1930s. The city hosted the first Republican National Convention in 1856. Democratic registrations increased after the Great Depression; however, the city was not carried by Democrat Franklin D. Roosevelt in his landslide victory of 1932 as Pennsylvania was one of only six states won by Republican Herbert Hoover. Voter turnout surged from 600,000 in 1932 to nearly 900,000 in 1936 and Roosevelt carried Philadelphia with over 60% of the vote. The city has voted Democratic in every presidential election since 1936. In 2008, Democrat Barack Obama drew 83% of the city's vote. Obama's win was even greater in 2012, capturing 85% of the vote. In 2016, Democrat Hillary Clinton won 82% of the vote.

As a result of the declining population in the city and state, Philadelphia has only three congressional districts of the 18 districts in Pennsylvania, based on the 2010 Census apportionment: the 2nd district, represented by Brendan Boyle; the 3rd, represented by Dwight Evans; and the 5th, represented by Mary Gay Scanlon. All three representatives are Democrats though Republicans still have some support in the city, primarily in the Northeast. Sam Katz ran competitive mayoral races as the Republican nominee in 1999 and 2003, losing to Democrat John Street both times.

Pennsylvania's longest-serving Senator, Arlen Specter, was an alumnus of the University of Pennsylvania who opened his first law practice in Philadelphia. Specter served as a Republican from 1981 and as a Democrat from 2009, losing that party's primary in 2010 and leaving office in January 2011.

Many of Philadelphia’s business enterprises were established in the 1700s, but the city’s economy has changed greatly. Such old and once-dominant industries as textile mills met stiff competition from the South and from abroad. Industry was given a boost by World War II but began to decline later; thousands of jobs were lost in the 1960s. Nonmanufacturing and service industries, however, continue to increase employment and now dominate the economy. High-technology industries such as communications, computer software, and Internet commerce became important in the late 20th century. Printing and publishing and food processing are major factors in the modern economy. Manufactures include chemicals, industrial machinery, fabricated metal products, electronics, transportation equipment, scientific instruments, apparel, paper products, rubber and plastic products, and primary metals. A decline has been evident in the migration of both people and businesses from the city to the suburbs. The Valley Forge area, best known as a Revolutionary War historic site, has become a nest of business and industrial locations. Much of this relocation is under the sponsorship of the Philadelphia Industrial Development Corporation.One of the mainstays of the economy in Philadelphia and much of eastern Pennsylvania from before the birth of the nation was the naval yard, which employed tens of thousands of workers in its prime. Ship building emerged as an important part of the economy in the late 18th century, and the Continental Congress commissioned five ships from Philadelphia during the Revolutionary War. A naval shipyard was opened in 1801 by an act of Congress of 1799, and the Philadelphia Naval Shipyard became one of the most important production sites for the navy. Efforts were made to keep the yard going even before it closed, and in 1997 an agreement was reached with a major Norwegian shipbuilder. Ship production began again in 2000, and the first ship built at the new Kvaener Philadelphia Shipyard was completed on March 2003.

Philadelphia is the center of economic activity in Pennsylvania with the headquarters of five Fortune 1000 companies located within city limits. As of 2019, the Philadelphia metropolitan area is estimated to produce a gross metropolitan product of $490 billion, an increase from the $445 billion calculated by the Bureau of Economic Analysis for 2017, representing the eighth largest U.S. metropolitan economy. Philadelphia was rated by the GaWC as a 'Beta' city in its 2016 ranking of world cities.With a gross domestic product of $388 billion, the city of Philadelphia alone ranks ninth among world cities and fourth in the nation. The city is also the nation's fourth-largest consumer media market, as ranked by the Nielsen Media Research.

The city is also home to the Philadelphia Stock Exchange. Philadelphia has shifted to an information technology and service-based economy. Financial activities account for the largest sector of the metro economy, and it is one of the largest health education and research centers in the United States. Philadelphia's history attracts many tourists, with the Liberty Bell receiving over 2 million visitors in 2010.

Philadelphia's economic sectors include higher education, manufacturing, oil refining, food processing, health care and biotechnology, telecommunications, tourism and financial services.The federal government has several facilities in Philadelphia. The Delaware Valley contains the headquarters of twelve Fortune 500 corporations, four of which are in Philadelphia proper. Fortune 500 companies in Delaware Valley include cable television and internet provider Comcast, insurance companies Colonial Penn, CIGNA and Lincoln Financial Group, energy company Sunoco, food services company Aramark and Crown Holdings Incorporated, chemical makers Rohm and Haas Company and FMC Corporation, pharmaceutical companies Wyeth and GlaxoSmithKline, aerospace and defense Boeing Rotercraft Systems and Lockheed Martin and automotive parts retailer Pep Boys.With the historic presence of the Pennsylvania Railroad, and the large ridership at 30th Street Station, Amtrak maintains a significant presence in the city. These jobs include customer service representatives and ticket processing and other behind-the-scenes personnel, in addition to the normal functions of the railroad.The city is also a legal center. It is home to the law schools of Penn, Drexel, Temple, Rutgers , Villanova, and Widener. The headquarters of the American Law Institute is located in the city as well as the Third Circuit Court of Appeals. Ten of the 100 largest law firms in the US have their headquarters or largest office in Philadelphia.Tourism is a major industry in Philadelphia, which was the 11th-most-visited city in the United States in 2008. It welcomed 710,000 visitors from foreign countries in 2008, up 29% from the previous year.

Shopping options in Center City include Fashion District Philadelphia, The Shops at Liberty Place, Jewelers' Row, South Street, Old City's 3rd Street Corridor, and a wide variety of standalone independent retailers. The Rittenhouse area, known as Philadelphia's outdoor shopping mall, includes Rittenhouse Row, a four-block section of Walnut Street, which has higher-end clothing chain stores and some hipster-inspired clothing stores. The parallel streets of Sansom and Chestnut have some high-end boutiques and clothing retailers. Old City, especially the 3rd Street corridor, has locally owned independent boutiques and art/design galleries. Midway between Old City and Broad Street is the Reading Terminal Market, with dozens of take-out restaurants, specialty food vendors, and small grocery store operators, a few of which are operated by Amish farmers from nearby Lancaster County.

Philadelphia has a few eclectic neighborhood shopping districts, which generally consist of a few blocks along a major neighborhood thoroughfare, such as in Manayunk or Chestnut Hill.

One of the first subway systems in the United States was established in the city in 1907 and remains a centrepiece of public transportation in Philadelphia. A complex system of public and private trolley and bus lines was consolidated in 1963 by the state legislature’s creation of the Southeastern Pennsylvania Transportation Authority to plan, develop, and coordinate a regional transportation system and to fund projects by the sale of bonds. Express buses provide rapid service between the inner and outer city. A high speed rail line connects Philadelphia with nearby communities in New Jersey and a ferry and rail line link the city with the renovated waterfront in Camden, New Jersey.

A joint New Jersey–Pennsylvania bridge commission operates 7 toll and 13 tax-supported bridges over the Delaware north of the city. The city is home to the first hospital in the British North American colonies, Pennsylvania Hospital, and the first medical school in what is now the United States, at the University of Pennsylvania . Penn, the city's largest private employer, also runs a large teaching hospital and extensive medical system. There are also major hospitals affiliated with Temple University School of Medicine, Drexel University College of Medicine, Thomas Jefferson University , and Philadelphia College of Osteopathic Medicine.

Together, health care is the largest sector of employment in the city. Several medical professional associations are headquartered in Philadelphia. With Philadelphia's importance as a medical research center, the region supports the pharmaceutical industry. Philadelphia is served by the Southeastern Pennsylvania Transportation Authority which operates buses, trains, rapid transit , trolleys, and trackless trolleys throughout Philadelphia, the four Pennsylvania suburban counties of Bucks, Chester, Delaware, and Montgomery, in addition to service to Mercer County, New Jersey and New Castle County, Delaware .

[Philadelphia's 30th Street Station is a major railroad station on Amtrak's Northeast Corridor with 4.4 million passengers in 2017 making it the third-busiest station in the country after New York City's Pennsylvania Station and Washington's Union Station. The PATCO Speedline provides rapid transit service to Camden, Collingswood, Westmont, Haddonfield, Woodcrest , Ashland , and Lindenwold, New Jersey, from stations on Locust Street between 16th and 15th, 13th and 12th, and 10th and 9th Streets, and on Market Street at 8th Street. William Penn planned Philadelphia with numbered streets traversing north and south, and streets named for trees, such as Chestnut, Walnut, and Mulberry, traversing east and west. The two main streets were named Broad Street and High Street converging at Centre Square which later became the site of City Hall.

Interstate 95 traverses the southern and eastern edges of the city along the Delaware River as the main north–south controlled-access highway, connecting Philadelphia with Newark, New Jersey and New York City to the north and with Baltimore and Washington, D. Interstate 676 links I-95 and I-76 through Center City by running below street level between the eastbound and westbound lanes of Vine Street. Route 30 extends westward from West Philadelphia to Lancaster. Philadelphia is a hub for Greyhound Lines. The Greyhound terminal is located at 1001 Filbert Street in Center City, southeast of the Pennsylvania Convention Center and south of Chinatown.

Since the early days of rail transportation in the United States, Philadelphia has served as a hub for several major rail companies, particularly the Pennsylvania Railroad and the Reading Railroad. The Pennsylvania Railroad first operated Broad Street Station, then 30th Street Station and Suburban Station, and the Reading Railroad operated Reading Terminal, now part of the Pennsylvania Convention Center. The two companies also operated competing commuter rail systems in the area. Additionally, the PATCO Speedline subway system and NJ Transit's Atlantic City Line operate successor services to southern New Jersey.

[In 1911, Philadelphia had nearly 4,000 electric trolleys running on 86 lines. Philadelphia is a regional hub of the federally owned Amtrak system, with 30th Street Station being a primary stop on the Washington-Boston Northeast Corridor and the Keystone Corridor to Harrisburg and Pittsburgh. 30th Street also serves as a major station for services via the Pennsylvania Railroad's former Pennsylvania Main Line to Chicago. As of 2018, 30th Street is Amtrak's third-busiest station in the country, after New York City and Washington.

A 2017 study by Walk Score ranked Philadelphia the fifth most walkable major city in the United States with a score of 79 out of 100, in the middle of the «very walkable» range. The city was just edged out by fourth place Miami , with the top three cities being New York, San Francisco, and Boston. Philadelphia placed fifth in the public transit friendly category, behind Washington, D. The city ranked tenth in the bike friendly cities category, with the top three cities being Minneapolis, San Francisco and Portland. The city has two filtration plants on the Schuylkill River and one on the Delaware River.

Exelon subsidiary PECO Energy Company, founded as the Brush Electric Light Company of Philadelphia in 1881 and renamed Philadelphia Electric Company in 1902, provides electricity to about 1.6 million customers and more than 500,000 natural gas customers in the southeastern Pennsylvania area including the city of Philadelphia and most of its suburbs. PGW serves over 500,000 homes and businesses in the Philadelphia area. [ Founded in 1836, the company came under city ownership in 1987 and has been providing the majority of gas distributed within city limits. In 2014, the City Council refused to conduct hearings on a $1.86 billion sale of PGW, part of a two-year effort that was proposed by the mayor.

Southeastern Pennsylvania was assigned the 215 area code in 1947 when the North American Numbering Plan of the Bell System went into effect. The geographic area covered by the code was split nearly in half in 1994 when area code 610 was created, with the city and its northern suburbs retaining 215. Overlay area code 267 was added to the 215 service area in 1997, and 484 was added to the 610 area in 1999. Area code 445 was implemented as an overlay for area codes 215 and 267 starting on February 3, 2018.