West Loop, Chicago in the context of "Jane Byrne Interchange"

The Loop is Chicago's central business district and one of the city's 77 municipally recognized community areas. Located at the center of downtown Chicago on the shores of Lake Michigan, it is the second-largest business district in North America, after Midtown Manhattan in New York City. It contains the world headquarters and regional offices of several global and national businesses, retail establishments, restaurants, hotels, museums, theaters, and libraries—as well as many of Chicago's most famous attractions. The district also hosts Chicago's City Hall, the seat of Cook County, offices of the state of Illinois, United States federal offices, and several foreign consulates. The intersection of State Street and Madison Street in the Loop is the origin point for the address system on Chicago's street grid, a grid system that has been adopted by numerous cities worldwide.

The Loop's definition and perceived boundaries have evolved over time. Since the 1920s, the area bounded by the Chicago River to the west and north, Lake Michigan to the east, and Roosevelt Road to the south has been called the Loop. It took its name from a somewhat smaller area, the 35 city blocks bounded on the north by Lake Street, on the west by Wells Street, on the south by Van Buren Street, and on the east by Wabash Avenue—the Union Loop formed by the 'L' in the late 1800s. Similarly, the "South Loop" and the "West Loop" historically referred to areas within the Loop proper, but in the 21st century began to refer to the entire Near South and much of the Near West Sides of the city, respectively.