Chicago is a major city in the U.S. state of Illinois. The city is the largest in the Midwest and the third-most populous city in the United States, with close to three million people. The Chicago Metropolitan area, informally known as Chicagoland, has a population of over 9.4 million in Illinois, Wisconsin, and Indiana making it the third largest in the United States. Chicago is located along the southwestern shore of Lake Michigan and is a major center of transportation, industry, politics, culture, finance, medicine and higher education. Chicago is informally called the "Second City," the "Windy City," and the "City of Big Shoulders" (from Carl Sandburg's poem Chicago).