Chicago O'Hare International Airport (IATA: ORD, ICAO: KORD, FAA LID: ORD) is a major international airport serving Chicago, Illinois, United States, located on the city's Northwest Side, approximately 17 miles (27 km) northwest of the Loop business district.

[11][12] As the first major airport planned after World War II, O'Hare's innovative design pioneered concepts such as concourses, direct highway access to the terminal, jet bridges, and underground refueling systems.

[14][15] In 2019, O'Hare had 919,704 aircraft movements, averaging 2,520 per day, the most of any airport in the world, in part because of a large number of regional flights.

The 2 million square feet (190,000 m2) plant, in the northeast corner of what is now the airport, needed easy access to the workforce of the nation's second-largest city, as well as its railroads and location far from enemy threat.

Douglas considered building airliners at Orchard but chose to concentrate civil production at its headquarters in Santa Monica, California.

[24] The United States Air Force used the field extensively during the Korean War; the airport then had no scheduled airline service.

[25] By 1960, the need for O'Hare as an active duty fighter base was diminishing, just as commercial business was picking up at the airport.

[27] In 1945, Chicago mayor Edward Kelly established a board to choose the site of a new airport to meet future demand.

After considering various proposals, the board decided upon the Orchard Field site and acquired most of the federal government property in March 1946.

[28] O'Hare was the site of the world's first jet bridge in 1958,[29][30] and successfully adapted slip form paving, developed for the nation's new Interstate highway system, for seamless concrete runways.

Although Chicago had invested over $25 million in O'Hare, Midway remained the world's busiest airport and airlines were reluctant to move until highway access and other improvements were completed.

The arrival of Midway's traffic quickly made O'Hare the world's busiest airport, serving 10 million passengers annually.

Within two years, that number would double, with Chicagoans boasting that more people passed through O'Hare in 12 months than Ellis Island had processed in its entire existence.

In the 1980s, after passage of US airline deregulation, the first major change at O'Hare occurred when TWA left Chicago for St. Louis as its main mid-continent hub.

[37] Although TWA had a large hangar complex at O'Hare and had started Constellation nonstops to Paris in 1958, by the time of deregulation its operation was losing $25 million a year under competition from United and American.

[40] Ultimately, Delta found competing from an inferior position at O'Hare too expensive and closed its Chicago hub in the 1990s, concentrating its upper Midwest operations at Cincinnati.

It was built between 1985 and 1987 on the site of the original Terminal 1; the structure, which includes 50 gates, is best known for its curved glass forms and the connecting underground tunnel between Concourses B and C.[41] The tunnel is illuminated with a neon installation titled Sky's the Limit (1987) by Canadian artist Michael Hayden, which plays an airy, slow-tempo version of Rhapsody in Blue.

Official reports at the end of the 1990s ranked O'Hare as one of the worst-performing airports in the United States based on the percentage of delayed flights.

[47] The OMP was the subject of legal battles, both with suburbs who feared the new layout's noise implications as well as with survivors of persons interred in a cemetery the city proposed to relocate; some of the cases were not resolved until 2011.

[48] These issues, plus the reduction in traffic as a result of the Great Recession, delayed the OMP's completion; construction of the sixth and final parallel runway (9C/27C) began in 2016.

)[51] The expansion will enable same-terminal transfers between international and domestic flights, faster connections, improved facilities and technology for TSA and customs inspections and much larger landside amenities such as shopping and restaurants.

[55] By terms of the agreement, total costs of $8.5 billion for the project are to be borne by bonds issued by the city, which will be retired by airport usage fees paid by airlines.

[78] The CTA Blue Line's north terminus is at O'Hare and provides direct service to downtown via the Milwaukee–Dearborn subway in the Loop and continuing to west suburban Forest Park.

I-90 continues as the Kennedy Expressway into downtown Chicago and becomes the Jane Addams Memorial Tollway northwest to Rockford and the Wisconsin state line.

The bees are maintained by 30 to 40 ex-offenders with little to no work experience and few marketable skills; they are primarily recruited from Chicago's North Lawndale neighborhood.

They are taught beekeeping but also benefit from the bees' labor, turning it into bottled fresh honey, soaps, lip balms, candles and moisturizers marketed under the beelove product line.

[85][86] More than 500 persons have completed the program, transferring to jobs in manufacturing, food processing, customer service, and hospitality; the repeat-offender rate is reported to be less than 10%.