Chicago is a city in the United States.
Chicago ( [ ʃᵻˈkɑːɡoʊ ] or [ ʃᵻˈkɔːɡoʊ ] ) , officially the City of Chicago , is the third-most populous city in the United States . United States . The capital is Washington , D.C. , and the largest city is New York City ; nine other major metropolitan areas -- each with at least 4.5 million inhabitants and the largest having more than 13 million people -- are Los Angeles , Chicago , Dallas , Houston , Philadelphia , Miami , Atlanta , Boston , and San Francisco .