Philadelphia, colloquially referred to as Philly, is the most populous city in the U.S. state of Pennsylvania. It ranks as the sixth-most populous city in the United States, with a population estimated at 1.57 million in 2025. The surrounding metropolitan area, known as the Delaware Valley, has a population of 6.33 million residents and is the ninth-largest metropolitan area in the nation.
The city is recognized for its significant contributions to culture, cuisine, and history. It maintains contemporary influence across various sectors, including business, technology, sports, and music.