Pittsburgh is 2.6% larger than Dayton, Ohio.
Area: 149 km2 calculated
Dayton is the sixth largest city in the U.S. state of Ohio and is the county seat of Montgomery County. Wikipedia
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