Squirrels can be found just about anywhere but down here any game land with some hardwood ridges or a good pin oak swamp is going to have plenty of grays and down east there are a few fox squirrels but I leave them be since they struggle to survive with the demise of the Loblolly pine here in NC.
I have visited Illinois around the Peoria area and stayed at a home near the Illinois River. I was impressed with the plentyful and huge fox squirrels everywhere. I did not hunt them as I had come there for the ducks on the river but always wanted to go back and try it. I saw plenty of squirrels in Maryland’s eastern shore including the Delmarva Fox Squirrel which was protected at the time so we had to let them be. They were fun to watch while on the deer stand though. There used to be a population of white squirrels in Chickahominy Park in Va but I have not heard anything about them in years. I beleive this is a WMA and it has been touted for good small game hunting in the past. Well good luck with planning a hunt. If you ever get down here to NC during the season I can steer you to some good squirrel hunting on public land.