Pittsburgh is 25% larger than San Francisco.
Area: 153 km2 calculated
Pittsburgh is the seat of Allegheny County and with a population of 305,841 is the second-largest city in the U.S. state of Pennsylvania. With a metropolitan CSA population of 2,659,937, it is the largest in both the Ohio Valley and Appalachia and the 20th-largest in the U.S. Wikipedia
Area: 122 km2 calculated
San Francisco, officially the City and County of San Francisco, is the cultural center and a leading financial hub of the San Francisco Bay Area and Northern California. Wikipedia