Blue Ridge Summit is an unincorporated community in Franklin County, Pennsylvania, United States, southwest of Gettysburg in the central part of the state, adjoining Pennsylvania's southern border with Maryland. It is less than 3 miles east of Pen Mar, Maryland. http://maps. google. com/maps?ll=39.717778,-77.506111&spn=0.1,0.1&t=m&q=39.717778,-77.506111 The community is known for being the birthplace of Wallis Simpson, the late wife of Prince Edward, Duke of Windsor.