The city of Chicago is located in Cook County in the northeastern corner of Illinois, United States, and on the southwest shore of Lake Michigan, one of the five Great Lakes in the United States. Chicago, the third most populous city in the United States, is the second largest commercial center in the United States, the largest futures market in the United States, and one of the famous international financial centers.

The Greater Chicago Area, composed of Chicago and its suburbs, is the third largest metropolitan area in the United States after New York City and Los Angeles. Chicago is located in the center of the North American continent and is the most important railway and aviation hub in the United States. Chicago is also one of the major financial, cultural, manufacturing, futures and commodity trading centers in the United States. Since its founding in 1833, after more than a hundred years of development, it has gradually become one of the most influential metropolises in the world. Common nicknames for Chicago include: "Second City", "Windy City", "Chi City", etc. In 2014, it received more than 50 million tourists from around the world.