The Naval History & Heritage Command, formerly the Naval Historical Center, is an Echelon II command responsible for the preservation, analysis, and dissemination of U.S. naval history and heritage located at the historic Washington Navy Yard. The NHHC is composed of 42 facilities in 13 geographic locations including the Navy Department Library, 10 museums and 1 heritage center, USS Constitution repair facility and detachment, and historic ship ex-USS Nautilus.