Pen Mar was one of the most popular resorts in the east for nearly fifty years.  It was named for it’s location on the border between Pennsylvania and Maryland.  In 1872 The Western Maryland Railroad completed its line across the Blue Ridge Mountains to Hagerstown, Maryland.  John Mifflin Hood, President of the Western Maryland, realized the potential for a summer resort in such a beautiful area just 70 miles from Baltimore.  Hood established Pen Mar Pak in 1877 on a thirteen acre site recommended by Peter Rouzer, founder of Rouzerville.
     For the first time in history, masses of people could leave the hot city streets for a day in the cool mountain air due to the fast and affordable excursion trains.  The entire area around the park grew rapidly into a first class summer resort.  By the turn of the century over a hundred hotels and boarding houses had been built.  Trolley service linked the park to surrounding communities, providing employment and recreation to local residents.
     By 1920 Pen Mar had become an institution.  Wealthy industrialists and Washington dignitaries built splendid summer homes and permanent residences in the developments of Monterey, Buena Vista, Blue Ridge Summit, Blue Mountain, Pen Mar.