About Chicago

Chicago ( (listen) shih-KAH-goh, locally also shih-KAW-goh) is the most populous city in the U.S. state of Illinois and the third-most populous in the United States, after New York City and Los Angeles. With a population of 2,746,388 in the 2020 census, it is also the most populous city in the Midwest. As the seat of Cook County (the second-most populous U.S. county), the city is the center of the Chicago metropolitan area, one of the largest in the world. On the shore of Lake Michigan, Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed. It grew rapidly in the mid-19th century; by 1860, Chicago was the youngest U.S. city to exceed a population of 100,000.