Chicago is 3 times larger than Springfield, Illinois.
Area: 608 km2 calculated
Chicago is the third most populous city in the United States, after New York City and Los Angeles. With 2.7 million residents, it is the most populous city in both the U.S. state of Illinois and the American Midwest. Wikipedia
Area: 205 km2 calculated
Springfield is the capital of the US state of Illinois and the county seat of Sangamon County with a population of 116,250, making it the sixth most populated city in the state. It is the largest city in central Illinois. Wikipedia