 The third segment was finished in 1933, which completed the paving of US 15 in Maryland.Around 1938, the U.S. Highway was resurfaced with asphalt from Emmitsburg to the Pennsylvania state line and from the south end of Frederick to Evergreen Point; in addition, a grade separation was constructed with the Western Maryland Railway in Thurmont.Several ferries crossed the Potomac River at Point of Rocks before the first bridge was constructed there in 1852.