Terminals
O'Hare has four numbered passenger terminals with nine lettered concourses and a total of 182 aircraft gates. Two or more additional terminal buildings are envisioned; there is the possibility of a large terminal complex for the west side of the field, with access from I-90 and/or the Elgin-O'Hare Expressway, if the runway reconfiguration is completed and passenger numbers require additional terminals.
All international arrivals at O'Hare (except flights from destinations with border preclearance) arrive at Terminal 5, as the other terminals do not have Customs facilities. Some airlines, such as United Airlines, American Airlines, Iberia and Lufthansa, will deplane aircraft at Terminal 5 and then, after passengers are offloaded, taxi the planes to other terminals (Terminal 1 for United and Lufthansa, for example) for boarding. This is done at least in part to make connections for passengers transferring from domestic flights to international flights easier.
Read more about this topic: O'Hare International Airport