There are two terminals at ATL, International and Domestic, and seven concourses. All concourses are accessible from either terminal so it does not matter which one you use. American Airlines flights might depart from gates at any of the concourses. You can search your flight number in google to see what gate and concourse has been used historically.
Terminal North
The check-in counter for American Airlines is located in the North Terminal.
Just ask an airport attendant, they are so helpful
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