Cincinnati is 32% larger than St. Louis.
Area: 224 km2 calculated
Cincinnati is the third largest city in Ohio and the 28th largest city in the United States by metropolitan population and the county seat of Hamilton County. Settled in 1788, the city is located on the border between Ohio and Kentucky at the confluence of the Ohio River and the Licking River. Wikipedia
Area: 170 km2 calculated
St. Louis is an independent city and a major United States port in eastern Missouri. The city reaches the western banks of the Mississippi River, which forms Missouri's eastern border with Illinois. At the 2010 census, St. Wikipedia