Terminal South.
Delta is normally located in the International Terminal and the South Terminal for Domestic. Due to the current construction, you should check the signs for temporary access through the North terminal when they need to shutdown the South Terminal.
Ronit, Delta is terminal south. If you are arriving at the Atlanta airport you will see red & blue terminal. Red is South. You will need to also need to check with gate. "D" is a concourse not a Terminal and then each concourse has gate numbers. Hope this helps.
Thanks! Your answer is awaiting moderation.