How long is the extension of the blue ridge mountain range that Nichol's Gap Road was built over?
Nichol's Gap Road:  The highway was built over the South Mountain (Maryland and Pennsylvania) via Nichol's Gap ( ) and down the Devils Racecourse into the Cumberland Valley, allowing access to the 1762 Hagerstown, Maryland. South Mountain (Maryland and Pennsylvania):  From the Potomac River near Knoxville, Maryland, in the south, to Dillsburg, Pennsylvania, in the north, the 70 mi range separates the Hagerstown and Cumberland valleys from the Piedmont regions of the two states.
i don't know