Philadelphia (http://philadelphiausa.travel), located in southeastern Pennsylvania, on the southern fringe of the mid-Atlantic region, is the fourth-largest urban area in the United States and the country's fifth-largest city. Often referred to as "Philly," the official city boundaries are actually quite large—what started as a much smaller city began annexing the surrounding districts and suburbs in the mid-19th century, and Philadelphia the city is now coterminous with Philadelphia the county. Altogether, Philadelphia's metropolitan area encompasses a total twelve counties in Pennsylvania, New Jersey and Delaware.
