>>2297152Well and the fold curves in the middle of the state, whereas for the WV/VA border, as you head south, the plateau/ridge-valley border is literally the state line for much of the border.
The answer is that the plate that collided into america forming those mountains approached from the south-east I guess, so the deformation caused by the plate impact was limited in northern PA.
The PA plateau section has a lot of beautiful spots.
The ridge-and-valley province of mountains represents the area closest to the collision of plates millions of years ago in the appalachian mountain building events - the plateau represents the area beyond the immediate impact of those forces