Pull up a chair. This gets kind of wild.
The county thing is straightforward. State legislatures can create or adjust county boundaries, or do away with them completely. Georgia has 159 counties, second only to Texas (yes, I had to look that up). Why so many? Because the Democrat primary in Georgia used something called a County Unit System that awarded more votes to rural counties than to urban. This led to a proliferation of rural counties. The County Unit System didn't hold up in the courts because it violated one person, one vote, but the number of counties remain. The General Assembly could simply do away with Fulton County by dividing it among its neighbors. I seriously doubt that will happen.
Ludowici, now there's a tale. Ludowici is a Georgia town on US 1. Before the interstates, US 1 was the main highway from northern states to Florida, and Ludowici set up a speed trap. Now, speed traps in small towns are notorious everywhere, so maybe it was sitting on US 1 that gave Ludowici notoriety.
Lester Maddox was the owner of the Pickrick Restaurant in Atlanta who violated the law by refusing to serve blacks. He stood at the door with a pickax handle to prevent blacks from entering, and I think I read where he had pickax handles set out in his restaurant where patrons could join in. Such were the times that he used this as a successful springboard into politics and became elected governor. He could also ride a bicycle backwards and would do so in parades - I kid you not. He also supposedly grabbed a contractor who tried to bribe him by the elbow and "escorted" him from his office.
Well, the speed trap in Ludowici was a sore point with Maddox, and he tried to do away with it. Discovering that the governor didn't have that authority over a town, he instead put up billboards on US 1 outside the city limits warning of a speed trap ahead. Now, state legislatures have the authority to incorporate or disincorporate towns as they see fit, and I dimly recall periodic threats to disincorporate Atlanta, but that was a long time ago. So it's interesting that Maddox didn't push to disincorporate Ludowici.