Questions about O'Hare International Airport, the main international airport serving Chicago, Illinois in the Midwestern United States, and a major hub for United Airlines and American Airlines.

Chicago O'Hare International Airport (IATA: ORD) is the larger of the two principal commercial airports serving the city of , Illinois, and the main international gateway to the region.

ORD has 9 passenger concourses, indicated by letters, divided among 4 passenger terminals, indicated by numbers. One of the busiest airports in the world, O'Hare is a hub for (mostly in Terminal 1) and (mostly in Terminal 3. It is also a focus city for several other carriers, though Southwest and other low-cost carriers are concentrated at Midway Airport (), Chicago's other major airport.

The airport is located to about 17 mi/27 km to the northwest of downtown Chicago (The Loop), to which it is connected by the CTA Blue Line and by Interstate 90, commonly known as the Kennedy Expressway. A shuttle bus also connects the airport to the Metra commuter rail system's O'Hare Transfer station. See Getting To and From O'Hare at the airport website for more information.

The airport's code, ORD, is taken from Orchard Field, its original name. It was named in 1949 in honor of Edward O'Hare, a decorated World War II pilot in the US Navy.