The Loop is the central business district of Chicago, Illinois. It is one of the city's 77 designated community areas. The Loop is home to Chicago's commercial core, City Hall, and the seat of Cook County. The community area is bounded on the north and west by the Chicago River, on the east by Lake Michigan, and on the south by Roosevelt Road, although the commercial core has significantly expanded into adjacent community areas. As a business center, some of the corporations the Loop is home to include the Chicago Mercantile Exchange (CME), the world's largest options and futures contracts open interest exchange; the headquarters of United Continental Holdings, one of the world's largest airlines; AON; Blue Cross Blue Shield; Hyatt Hotels Corporation; BorgWarner, and dozens upon dozens of other major corporations.

The Loop, along with the rest of downtown Chicago, is the second largest commercial business district in the United States, after New York City's Midtown Manhattan. Its financial district near LaSalle Street is home to the CME Group's Chicago Board of Trade and Chicago Mercantile Exchange.