O'Hare International Airport (IATA: ORD, ICAO: KORD, FAA LID: ORD), typically referred to as O'Hare Airport, Chicago O'Hare, or simply O'Hare, is an international airport located on the Northwest Side of Chicago, Illinois, 14 miles (23 km) northwest of the Loop business district, operated by the Chicago Department of Aviation and covering 7,627 acres (3,087 ha). O'Hare has non-stop flights to 228 destinations in North America, South America, Europe, Africa, Asia and Oceania.
Established to be the successor to Chicago's "busiest square mile in the world", Midway Airport, O'Hare began as an airfield serving a Douglas manufacturing plant for C-54 military transports during World War II. It was named for Edward "Butch" O'Hare, the U.S. Navy's first Medal of Honor recipient during that war. Later, at the height of the Cold War, O'Hare served as an active fighter base for the Air Force.
As the first major airport planned post-war, O’Hare's innovative design pioneered concepts such as concourses, direct highway access to the terminal, jet bridges, and underground refueling systems. It became famous as the first World's Busiest Airport of the jet age, holding that distinction from 1963 to 1998; today, it is the world's sixth-busiest airport, serving 83 million passengers in 2018.
O'Hare is unusual in that it serves as a major hub for more than one of the three U.S. mainline carriers; it is United's largest hub in both passengers and flights, while it is American's third-largest hub. It is also a focus city for Frontier Airlines and Spirit Airlines.
While Terminals 2 and 3 remain of the original design, the airfield has seen radical modernization, and the terminal complex is beginning an expansion of passenger facilities that will remake it as North America's first airport built around airline alliances.