Los Angeles County, California is 17 times larger than Chicago.
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: 10,580 km2 calculated
Los Angeles County, also known as L.A. County, officially the County of Los Angeles, is a county in the U.S. state of California. As of the 2010 U.S. Census, the county has a population of 9,818,605, making it the most populous county in the United States. Wikipedia