Des Moines, Iowa is 64% larger than Rochester, Minnesota.
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
Area: 144 km2 calculated
Rochester is a city in the U.S. State of Minnesota and is the county seat of Olmsted County. Located on the Zumbro River's south fork, the city has a population of 106,769 according to the 2010 United States Census. The U.S. Census Bureau estimated 2013 population is 110,742. Wikipedia