Chicago (ⁱ/ʃɪˈkɑːɡoʊ/ or /ʃɪˈkɔːɡoʊ/) is a city in the U.S. state of Illinois, and is the third most populous city in the United States, and the most populous city in the American Midwest with over 2.8 million residents. 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, with an estimated 9.8 million people. Chicago is the county seat of Cook County, though a small portion of the city limits also extend into DuPage County.