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[[File:Sears TowerChicago downtown.jpg|thumb|260px|left|Looking north on the Chicago River south of Harrison Street. The tall black building is the Sears Tower (now named Willis (née SearsTower) Tower; the building is in the foreground is 311 South Wackerdistance.]]
'''Chicago''' is a city located in the northeastern corner of the state of [[Illinois]] on the shore of the southwestern tip of [[Lake Michigan]]. Chicago is located mostly within [[Cook County]], but a corner of its O'Hare Airport is in [[DuPage County]]. It is the largest city in Illinois and the third-largest city in the [[United States]], with 2.8 million residents, after New York City and Los Angeles.<ref>http://quickfacts.census.gov/qfd/states/17/1714000.html</ref>. The Chicago metropolitan area, which extends from southern [[Wisconsin]] to northeastern [[Indiana]] and is often called "Chicagoland", contains 9.3 million people. <ref>http://www.census.gov/population/estimates/metro_general/2006/CSA-EST2006-alldata.csv</ref> It is the dominant city of the Midwest for transportation, trade, finance and high culture, and only reluctantly gave up the "second city" title to [[Los Angeles]] in the 1970s.