Portland, Oregon is 1.7% larger than Philadelphia.
Area: 370 km2 calculated
Philadelphia is the largest city in the Commonwealth of Pennsylvania, the fifth-most-populous city in the United States, and the core of the sixth-largest metropolitan area in the country. Wikipedia
Area: 376 km2 calculated
Portland is the largest city by population in the U.S. state of Oregon, near the confluence of the Willamette and Columbia rivers. Wikipedia