Cedar Rapids, Iowa is 44% larger than Peoria, Illinois.
Area: 187 km2 calculated
Cedar Rapids is the second largest city in Iowa and is the county seat of Linn County. The city lies on both banks of the Cedar River, 20 miles north of Iowa City and 100 miles east of Des Moines, the state's capital and largest city. Wikipedia
Area: 130 km2 calculated
Peoria is a city in and the county seat of Peoria County, Illinois, United States, and the largest city on the Illinois River. Established in 1691 by the French explorer Henri de Tonti, Peoria is the oldest European settlement in Illinois, and is named after the Peoria tribe. Wikipedia