The Loop or Chicago Loop is one of 77 officially designated community areas located in the City of Chicago, Illinois, United States. It is the historic commercial center of downtown Chicago. It is the seat of government for Chicago and Cook County, as well as the historic theater and shopping district (including State Street, "that great street" in the words of the song made famous by Frank Sinatra).

As established in social research done by the University of Chicago in the 1920s, the Loop is a defined community area of Chicago. Chicago's central business district community area is bounded on the west and north by the Chicago River, on the east by Lake Michigan, and on the south by Roosevelt Road, although the commercial core has expanded into adjacent community areas.

The community area includes Grant Park and one of the largest art museums in the United States, the Art Institute of Chicago. Other major cultural institutions that call this area home include the Chicago Symphony Orchestra, the Lyric Opera of Chicago, the Goodman Theatre, the Joffrey Ballet, the central public Harold Washington Library, and the Chicago Cultural Center.

Chicago (ⁱ/ʃɪˈkɑːɡoʊ/ or /ʃɪˈkɔːɡoʊ/) is the largest city in the US state of Illinois and the third most populous city in the United States after New York City and Los Angeles. The city has around 2.7 million residents. Its metropolitan area, sometimes called "Chicagoland", is the third largest in the United States, with an estimated 9.8 million people. Chicago is the county seat of Cook County, though a small portion also extends into DuPage County.

Chicago was incorporated as a city in 1837, near a portage between the Great Lakes and the Mississippi River watershed. Today, Chicago is listed as an alpha+ global city by the Globalization and World Cities Research Network, and ranks seventh in the world on the 2012 Global Cities Index. The city retains its status as an international hub for finance, industry, telecommunications and infrastructure, with O'Hare International Airport being the second busiest airport in the world in terms of traffic movements. In 2008^[update], the city hosted 45.6 million domestic and overseas visitors. Among metropolitan areas, Chicago has the 4th largest Gross Domestic Product (GDP) in the world, ranking just behind Tokyo, New York City, and Los Angeles. Chicago is one of the most important Worldwide Centers of Commerce and trade.