How many times has this topic come up? Texas and Florida are their own regions; DC/NoVA/MD is sort of its own little entity... not quite Northeast, but too Northern to be truly Southern.
Atlanta is the clear hub and geographic crossroads of the South, with Georgia being the state most people (myself included) readily associate with the region. It's equidistant to two other booming "new South" cities in Charlotte and Nashville and, driving-mile wise, is also (relatively) equally proximate to DC, Miami, Dallas, and Houston. Atlanta is also a big college football town and home to an SEC (absolutely synonymous with Southern US culture) powerhouse in the UGA Bulldogs (technically Athens, but same metro area).
https://fivethirtyeight.com/features...-in-the-south/