The world's busiest airport when measured by takeoffs and landings, Chicago O'Hare International Airport (ORD) is located about 17 miles northwest of downtown Chicago. Serving northeastern Illinois, as well as nearby communities in Wisconsin and Indiana, the airport serves as a hub for American Airlines and United Airlines. It is also a focus city for Frontier Airlines and Spirit Airlines. O'Hare Airport consists of four terminals with nine concourses and more than 180 gates, as well as eight runways. Non-stop flights are available to about 210 destinations. This includes more than 150 destinations within the United States, plus cities in Canada, Mexico, the Caribbean, South America, Europe and Asia.