Chicago (IPA: /ʃɪˈkɑ�goʊ/), is a city in the state of Illinois and the largest in the Midwest. With its population of over 2.8 million people located almost entirely in Cook County (a portion of the city's O'Hare International Airport overlaps into DuPage County), Chicago is the third largest city in the United States. The population of Chicago's metropolitan area, which covers several counties, contains over 9.7 million people in Illinois, Wisconsin and Indiana, making it the third largest metropolitan area in the U.S.Population in Metropolitan and Micropolitan Statistical Areas Ranked by 2000 Population for the United States and Puerto Rico (CSV). U.S. Census Bureau (December 30 2003). Retrieved on September 14, 2006. Chicago has been classified as an alpha world city for its worldwide economic influence.Chicago in the World City Network Globalization and World Cities Study Group and Network

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