[quote=@Comrade Doge]
What would be the factions in Atlanta
[/quote]

A few gangs would have formed raider gangs, and their might be a few slavers, but I don't think a faction like the Enclave or even the Brotherhood would be around, especially since the Brotherhood is West coast.  You could make one up if you want.  Maybe a local military group or police group formed a faction to fight the gangs.