The Naval History & Heritage Command (NHHC) is at the historic Washington Navy Yard. It is an Echelon II command responsible for the preservation, analysis, and dissemination of U.S. naval history and heritage. The NHHC is composed of 42 facilities in 13 geographic locations. This includes the Navy Department Library, ten museums and one heritage center, USS Constitution repair facility and detachment, and Historic ship NAUTILUS.