Chicago O'Hare International Airport (IATA: ORD, ICAO: KORD, FAA LID: ORD), also known as O'Hare Airport, O'Hare Field, Chicago International Airport, Chicago O'Hare or simply O'Hare, is an international airport located on the Far Northwest Side of Chicago, Illinois, United States, 17 miles (27 km) northwest of the Loop. It is the primary airport serving the Chicago area, with Midway Airport, about 10 miles (16 km) closer to the Loop, serving as a secondary airport. It is operated by the City of Chicago Department of Aviation. Most of O'Hare Airport is in Cook County, but a section of the southwest part of the airport is in DuPage County. The airport is located within a section of the City of Chicago contiguously connected to the rest of the city via a narrow strip of land about 200 ft (61 m) wide, running along Foster Avenue, from the Des Plaines River to the airport. This land was annexed into the city limits in the 1950s to assure the massive tax revenues associated with the airport would go to the city. The strip is bounded on the north by Rosemont and the south by Schiller Park.
O'Hare is the busiest airport in the world by number of takeoffs and landings—a title it reclaimed in 2014, beating out Hartsfield-Jackson Atlanta International Airport (which had the title from 2005-2013). Until 1998, O'Hare was also the busiest airport in the world in number of passengers. It was surpassed mainly due to limits imposed on the airport by the federal government to reduce flight delays. As of 2014, O'Hare is the sixth busiest airport in the world by passenger traffic. O'Hare also has the most number of runways (8) of any major international airport. As of September 2014, O'Hare has direct service to a total of 210 destinations, including 153 domestic destinations in the United States and 57 international destinations in North America, South America, Asia and Europe. O'Hare is among a select group of airports worldwide with the distinction of serving more than 200 destinations, along with Frankfurt Airport, Amsterdam Airport Schiphol, Charles de Gaulle Airport, Hartsfield–Jackson Atlanta International Airport, Dallas/Fort Worth International Airport, Munich Airport, and Dubai International Airport.
O'Hare is currently a major hub for American Airlines and United Airlines, as well as a hub for regional carrier Air Choice One and a focus city for Frontier Airlines and Spirit Airlines. It is the second largest passenger carrying hub for United after Houston's George Bush Intercontinental Airport carrying 15.3 million passengers annually, and largest by number of daily flights, operating a total of 585 flights daily. O'Hare is American's second largest hub, behind Dallas/Fort Worth International Airport, and third largest by number of daily flights, operating a total of 201 mainline flights daily.
O'Hare has been voted the "Best Airport in North America" for 10 years by two separate sources: Readers of the U.S. Edition of Business Traveler Magazine (1998–2003) and Global Traveler Magazine (2004–2007). Travel and Leisure magazine's 2009 "America's Favorite Cities" ranked Chicago's Airport System (O'Hare and Midway) the second-worst for delays, New York City's airport system (JFK, Newark Liberty, and LaGuardia) being the first. O'Hare currently accounts for over a sixth of the nation's total flight cancellations.