Chicago... is the most populous city in the U.S. state of Illinois, and the third most populous city in the United States, with approximately 2.7 million residents.[1] Its metropolitan area (also called "Chicagoland"), which extends into Indiana and Wisconsin, is the third-largest in the United States, after those of New York City and Los Angeles,[4][5][6] with an estimated 9.8 million people. Chicago is the county seat of Cook County,[7] though a small portion of the city limits also extend into DuPage County.

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