 The U.S. Highway is known as Catoctin Mountain Highway from the Virginia state line at Point of Rocks north to US  340 near Jefferson and from MD 26 in Frederick north to the Pennsylvania state line near Emmitsburg.US 15 is also part of Jefferson National Pike along its freeway concurrency with US 340 and the Frederick Freeway between US 340 and MD 26.In July 2004, the Maryland General Assembly designated the highway the 115th Infantry Regiment Memorial Highway; a marker honoring the 115th Infantry Regiment was completed in the median of US 15 in Emmitsburg in July 2006.