Oklahoma City is 13 times larger than Peoria, Illinois.
Area: 1,682 km2 calculated
Oklahoma City is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, the city ranks 27th among United States cities in population. The population grew following the 2010 Census, with the population estimated to have increased to 610,613 as of July 2013. 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