MD 648A begins at an intersection with MD 450 (Baltimore-Annapolis Boulevard/Governor Ritchie Highway) just east of the Naval Academy Bridge that crosses the Severn River into the city of Annapolis.
MD 648E, which is the longest section of MD 648, is mostly located in Anne Arundel County; a small portion of the highway passes through the southeastern corner of Baltimore County before heading into Baltimore, where the highway is maintained by the Baltimore City Department of Transportation.