Wanderlust World Wanderlust World Yes, Philadelphia is in the state of Pennsylvania. It is the Commonwealth's largest city (population ~1.6 million) and the sixth-largest in the U.S. Founded in 1682 by William Penn, it served as the nation's first capital (1790–1800) and is where the Declaration of Independence and Constitution were signed. Today, it remains a major economic, cultural, and educational center, famed for its historic sites (Independence Hall, Liberty Bell), museums, universities, and vibrant neighborhoods.