Des Moines, Iowa is 4.8% larger than Cincinnati.
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: 235 km2 calculated
Des Moines is the capital and the most populous city in the U.S. state of Iowa. It is also the county seat of Polk County. A small portion of the city extends into Warren County. It was incorporated on September 22, 1851, as Fort Des Moines which was shortened to "Des Moines" in 1857. Wikipedia