Chicago O'Hare International Airport handles millions of passengers across four active terminal buildings and nearly 200 gates. Finding your way between Concourse B and Terminal 5 without a clear plan often leads to missed tight connections or unnecessary security re-checks.
This guide breaks down the exact layout of O'Hare's terminals, how airside and landside transfers actually work, and the quickest walking routes between concourses so you don't waste time wandering the corridors.
Decoding the Terminal and Gate Layout
O'Hare operates Terminals 1, 2, 3, and 5. Terminal 4 does not exist as a passenger terminal (it was formerly the international terminal in the 1980s and now serves as a bus facility).
- Terminal 1: Home to United Airlines and its partners. It splits into Concourse B (Gates B1-B22) and Concourse C (Gates C1-C31). Both concourses connect airside via a massive underground neon-lit pedestrian tunnel equipped with moving walkways.
- Terminal 2: Primarily handles domestic carriers like Delta and JetBlue, featuring Concourse E (Gates E1-E4.5) and Concourse F (Gates F1-F28). Terminal 2 sits directly between Terminals 1 and 3, allowing seamless airside walking between all three domestic buildings.
- Terminal 3: Serves American Airlines and other domestic carriers. It features Concourse G (Gates G1-G21), Concourse H (Gates H1-H16), Concourse K (Gates K1-K20), and Concourse L (Gates L1-L10).
- Terminal 5: The international terminal, handling all arriving international flights that require customs clearance (except for airlines with U.S. Border Preclearance), along with foreign flag carriers. It contains Gates M1-M40.
Navigating Airside Transfers Between Terminals
Moving between domestic terminals (1, 2, and 3) doesn't require exiting security. You can walk entirely airside.
If you land in Terminal 3 (Concourse G) and your connecting flight departs from Terminal 1 (Concourse B), follow overhead signs toward Terminal 1. You'll walk through the central hub near the junction of Terminals 1, 2, and 3 where the main food courts and customer service desks are located. This walk takes roughly 10 to 15 minutes at a brisk pace.
Terminal 5 is completely isolated from Terminals 1, 2, and 3. There is no airside pedestrian walkway connecting Terminal 5 to the rest of the airport. If you transfer between Terminal 5 and a domestic terminal, you must exit the secure area, take the Airport Transit System (ATS) train to the correct terminal, and clear TSA security checkpoints again.
Using the Airport Transit System
The Chicago Department of Aviation operates the Airport Transit System (ATS), a 24/7 automated people mover connecting all four passenger terminals, the multi-modal facility, and economy parking lots.
Trains arrive every few minutes, and the ride between Terminal 3 and Terminal 5 takes about five minutes. Always factor in an extra 25 to 30 minutes when your itinerary involves a transfer to or from Terminal 5 due to the train ride and security re-screening process.
Common Mistakes to Avoid
Travelers frequently make specific errors that jeopardize tight connections at O'Hare:
- Assuming Terminal 5 is walkable: Trying to find an indoor walking path to Terminal 5 wastes critical minutes. Always use the ATS train outside security or airside shuttle buses if provided by your airline for international-to-international connections.
- Ignoring Concourse Lettering: Gates at O'Hare start with letters that correspond to specific concourses, not terminals. Concourse names don't always match terminal numbers sequentially, which confuses first-time flyers. Double-check your boarding pass for both the letter and number.
- Forgetting Customs Delays: When arriving on an international flight at Terminal 5, every passenger must clear U.S. Customs and Border Protection, collect checked baggage, re-check bags at the transfer counter, and clear TSA security again—even if you have a domestic connection.
Frequently Asked Questions
How long does it take to walk between Terminals 1 and 3?
Walking briskly between Terminal 1 and Terminal 3 takes about 10 minutes airside. If you have mobility restrictions or heavy luggage, add extra time and utilize the moving walkways located throughout the central connecting corridors.
Where is the TSA PreCheck located in Terminal 1?
TSA PreCheck lanes are available at the main security checkpoints in all terminals. In Terminal 1, the checkpoint is located on the departures level near the entrance to Concourse B and C ticketing lobbies.
Can I walk between Terminal 5 and the domestic terminals?
No. Terminal 5 is separated from the rest of the airport. You must take the ATS train to travel between Terminal 5 and Terminals 1, 2, or 3.
What should I do if my gate changes at the last minute?
Check the digital flight information display screens located throughout every concourse, or refresh your airline's mobile app. O'Hare is large, so identify your new gate location immediately and head directly there using overhead directional signage.
