Glen Arm was once the home to a Grumman aircraft manufacturing plant. Today, the building serves as the American headquarters of and a warehouse for Ulla Popken women's clothing. Until 1958, this community was served by the Maryland and Pennsylvania Railroad at milepost 14.5. Glen Arm was home to American Attorney General, Charles Joseph Bonaparte, who was a great nephew of Napoleon, the French Emperor. While Attorney General, Charles Joseph Bonaparte created the Bureau of Investigation (now the FBI).