Aurora, illinois is 2.8 times larger than Joliet, Illinois.
Area: 412 km2 calculated
Aurora is a city in DuPage, Kane, Kendall, and Will counties in the U.S. state of Illinois. The second most populous city in the state, it is the 19th largest city in the Midwest and the 112th largest city in the country. Wikipedia
Area: 147 km2 calculated
Joliet is a city in Will and Kendall counties in the US state of Illinois, located 40 miles southwest of Chicago. It is the county seat of Will County. As of the 2010 census, the city was the fourth-most populated in Illinois, with a population of 147,433. Wikipedia