Illinois is located in the Midwestern United States, bordered by Lake Michigan to the east, Wisconsin to the north, Iowa and Missouri to the west, and Kentucky to the south. It has a humid continental climate with hot summers and cold winters. Major cities include Chicago, Aurora, Rockford, and Joliet. Transportation includes O'Hare International Airport and highways. Agriculture is a key industry, with major crops like corn, soybeans, and wheat. Residents have adapted to the climate by dressing for heat waves and winter weather, and infrastructure has been modified with dams, bridges, and use of waterways.