There was a Campbell County Georgia. It was located in what now is the lower part of Fulton Co. It was merged with Fulton in the depression. The first county seat was Campbelton located on a bluff above the Chattahoochee River. It's just a ghost town now with only the old town square and a few houses. The courthouse was later moved to Fairburn. There is an historical society for the former county but I know not its address. In the first years, Campbell County was quite large and included portions of present Fayette, Clayton, Douglas and Cobb counties. Godspeed.....Patrick