Chicago Midway International Airport (IATA: MDW, ICAO: KMDW, FAA LID: MDW) is a major commercial airport on the southwest side of Chicago, Illinois, located approximately 12 miles (19 km) from the city's Loop business district, and divided between the city's Clearing and Garfield Ridge communities.

Originally named Chicago Air Park,[8] Midway Airport was built on a 320-acre (130 ha) plot in 1923 with one cinder runway mainly for airmail flights.

More construction was funded in part by $1 million from the Works Progress Administration; the airport expanded to fill the square mile in 1938–41 after a court ordered the Chicago and Western Indiana Railroad to reroute tracks that had crossed the square along the northern edge of the older field.

The March 1939 OAG shows 47 weekday departures: 13 on United, 13 American, 9 TWA, 4 Northwest, and two each on Eastern, Braniff, Pennsylvania Central, and C&S.

[14] Unfortunately, Midway being surrounded by buildings on all sides meant that the airport was running out of room; its runways were too short to safely handle larger four-engine jetliners (the Boeing 707 and Douglas DC-8) that appeared in 1959.

Lighter aircraft like turboprop Lockheed L-188 Electras and Vickers Viscounts could have continued to fly out of Midway, but O'Hare's new terminal opened in 1962, allowing airlines to consolidate their flights.

By 1967, reconstruction began at the airport, adding three new concourses with 28 gates and three ticket counters,[11] and in 1968, the city invested $10 million in renovation funds.

Midway Airlines arrived on October 31, 1979, with DC-9 nonstops to Kansas City, Detroit and Cleveland Lakefront; they expanded greatly in the 1980s.

[18] The Carlton Midway Inn moved to allow the Chicago Transit Authority to create a new CTA terminal at the airport on Halloween 1993.

[11] Midway Airport serves as the terminus for the Orange Line, which traverses the southwestern section of the city before encircling the Loop.

The garage is connected to the Midway terminal building for convenient access to ticket counters and baggage claim areas.

[11] Continuing with the expansion project, a pedestrian bridge over Cicero Avenue was built in 2000, connecting the new terminal to the new concourses.

[9] In 2001 the new 900,000-square-foot (84,000 m2) Midway Airport terminal building opened, with larger ticket counters, spacious baggage claim areas, traveler information, and a short walking distance to gates.

Following the September 11 attacks, which resulted in a drop in passenger service, along with other problems for the airline industry, both Vanguard and National ceased operations at Midway and became defunct in 2002, with MetroJet being dissolved and refolded into US Airways' main line in late 2001.

[9] A new 6,300-space economy parking garage, including a new bridge and roadway for buses shuttling passengers to and from the terminal, opened in December 2005.

The consortium operating under the name of Midway Investment and Development Company LLC consisted of Vancouver Airport Services, Citi Infrastructure Investors, and Boston's John Hancock Life Insurance.

[25] In September 2013, Mayor Rahm Emanuel terminated new negotiations to privatize the airport, noting that the process was no longer competitive after one of the two finalists had backed out.

The one remaining was Great Lakes Airport Alliance – a partnership of Macquarie Infrastructure and Real Assets and Ferrovial.

[28] As the current terminal opened just a few months prior to the September 11th attacks, the security area was quickly rendered too small for the new screening measures and subsequently was forced to expand inward, taking away from space in the concourses.

Space that is reclaimed by moving security outward into the bridge will be redeveloped with an expansion of the central food court.

The main parking garage is being extended eastward over the CTA L tracks to add 1,500 spaces and streamline the entrance way.

[31] Runway 13L/31R was permanently closed after 82 years on August 9, 2023, and was converted to Taxiway H.[citation needed] Midway has 43 aircraft gates on three concourses.

River Valley Metro operates a commuter shuttle connecting the airport to Manteno and Bourbonnais in Kankakee County.

[48] On December 8, 1972, United Air Lines Flight 553, a Boeing 737-200, crashed into a residential area outside Midway during landing.