O'Hare International Airport Terminal Map

O'Hare sits about 27 km from the city centre and handles around 84.8 million passengers a year (2025). It is a hub under construction: the terminals are numbered 1, 2, 3 and 5 — there is no Terminal 4 — and that single fact is the most common source of confusion here. At the same time the airport is carrying out its largest rebuild in decades.

The four terminals

Why is there no 4? The number was skipped historically, and the surviving "4" is only a stop on the airport's internal transit train, not a terminal. A boarding pass that says T5 is entirely normal — you have not missed T4.

• ATS train — free, linking every terminal, the parking garages and the car hire centre; this is the main way to change building.
• United is in T1/T2, American in T3 and most international flights in T5 — moving between the three means taking the ATS or a walking connector.

Our diagram draws only the four buildings 1, 2, 3 and 5 and leaves the slot for 4 empty precisely to make that skipped number clear.

Transfers and connections

1. Cross-terminal connections are the norm at O'Hare: United to American, or domestic to international, both need 2–3 hours.
2. United to United is completed within T1/T2 and American to American within T3 — the smoothest combinations.
3. T5 is reached from the other buildings by ATS, with a wait plus ride of about 15–20 minutes — build that into your buffer.

Routes and flights

• Routes — around 50 airlines flying to about 250 destinations; long-haul points include London, Frankfurt, Paris, Madrid, Rome, Beijing, Shanghai, Tokyo, Seoul, Delhi, Tel Aviv, Toronto and Mexico City.
• Flights — 84.81 million passengers in 2025 (+6% year on year, sixth worldwide), with more than 857,000 aircraft movements — reclaiming the title of the world's busiest airfield.
• Aircraft — main bases are United (T1/T2) and American Airlines (T3), followed by oneworld and Star Alliance carriers; the fleet is 737 and A320 family narrowbodies, with 787, 777 and A350 on long-haul.

Getting into Chicago

• CTA Blue Line — runs 24 hours, about 45 minutes direct to the city centre, a reliable choice for a late arrival, and the fare is very low.
• Taxi / ride-hailing — about 27 km, 30 minutes without traffic, and markedly longer at peak times or in bad weather.
• Metra commuter rail — services link to the city centre, useful if you are staying in the western suburbs.
• Airport buses — cover the city centre hotel district.

Practical tips

• The airport is in the middle of a large-scale rebuild (a new satellite concourse and the Global Terminal, built in phases), so routes inside the buildings may be adjusted at short notice — check the airport's or your airline's latest guidance before you travel.
• Chicago winters bring frequent snow and wind, and delays and de-icing waits are common, so allow generous margins for a winter connection.
• For a late-night arrival, take the Blue Line first — it is one of the few airport rail lines that runs through the night.