Nathan Bedford Forrest is an excellent example. Point well taken.

It would still be well to understand that at the time of the Civil War most Southern boys had a better education than their children and grandchildren received.

As for more isolated areas, Southern counties where most people were poor, educational opportunities were few and access to the outside world was limited, these tended to be Unionist strongholds. It's not entirely clear why that was, but there seems to be a strong corelation.