I would depend on if you wanted to be adventurous or go where it's known. The only place I know of that I can find it, is Flint Ridge Ohio. I would also read as many past posts on the subject and hopefully get some tips.
On the adventure side, Georgia, West Virginia, Tennessee and Kentucky all hold some good rock if you can find it. NC has some good rock as you know, but that has seemed to be an "adventurous option" also, at least to me.