5 Atlantic Coastal & Erie Pl. Online version Sort information as being about either the city of Philadelphia, PA; the city of Erie, PA; or both. by Teresa Haug 1 Philadelphia Only 2 Erie Only 3 Both Erie and Philadelphia many suburbs largest city river port city 40 feet above sea level nearly 1.6 million people huge manufacturing center more tourist attractions Franklin Institute subway system closer to Atlantic Ocean oil refineries produces medicines southeast PA professional sports lake port city fourth largest city ships on the Great Lakes about 96,471 population lake effect snow Presque Isle orchards shipping center port city plain land