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Aerial photo of the Smithsonian Institution Building Smithsonian Institution Building
Aerial View of the Castle and AIB Revitalization of the Historic Core


The Smithsonian Institution Building, the “Castle,” is the Institution’s first home and its symbolic heart. The Arts and Industries Building opened in 1881 as the first home of the National Museum. Together, these two buildings comprise the Smithsonian’s Historic Core. Both buildings are in need of major revitalization, work that will include new, efficient heating, air conditioning, and ventilation systems; new electrical and plumbing systems, and new telecommunications, security and life safety systems. A new, underground Central Utility Plant will provide mechanical and electrical infrastructure and a new Consolidated Loading Facility will improve the efficiency and safety of materials handling in the South Mall Campus. A goal of the revitalization will prioritize exterior and interior restoration, and to provide efficient and accessible space for visitors and staff. Public spaces will be restored after years of piecemeal remodeling that has diminished their original proportions and appearance.

Public Consultation Meeting Information

View the Amendment to the Programmatic Agreement

Download the Assessment of Effects on Historic Resources

View the Programmatic Agreement

Revitalization of the Historic Core - Section 106


Consulting Parties Meeting #18
January 17, 2024

Consulting Parties Meeting #17
October 25, 2023

Consulting Parties Meeting #16
September 27, 2023

Consulting Parties Meeting #15
July 26, 2023

Consulting Parties Meeting #14
June 28, 2023

Consulting Parties Meeting #13
May 24, 2023

Consulting Parties Meeting #12
April 27, 2023

Consulting Parties Meeting #11
March 22, 2023

Consulting Parties Meeting #10
February 22, 2023

Consulting Parties Meeting #9
January 25, 2023


Consulting Parties Meeting #8
November 30, 2022

Consulting Parties Meeting #7
October 26, 2022

Consulting Parties Meeting #6
September 28, 2022

Consulting Parties Meeting #5

August 24, 2022

Consulting Parties Meeting #4
June 15, 2022 


Consulting Parties Meeting #3
November 16, 2021 and December 14, 2021

Information Presentations

Meeting Minutes

View the Draft Assessment of Effects on Historic Resources

Consulting Parties Meeting #2

May 26 and 27, 2021

Information Presentations

Consulting Parties Meeting #1 

Jan 13, 2021

Project Background

There is a need for comprehensive rehabilitation of the Smithsonian Institution Building (SIB or "the Castle") and the Arts and Industries Building (AIB) in order to address physical deterioration, obsolete systems, and non-compliance with construction, accessibility, and life-safety codes. Construction of a Central Utility Plant and enhanced Loading Dock will link and serve the SIB and AIB buildings. Both the SIB and AIB are National Historic Landmarks, listed in the National Register of Historic Places, and part of the National Mall Historic District.

After June 2022, this project was resequenced, with the Revitalization of the Castle proceeding first. The AIB will be a separate future project that may include the Central Utility Plant.

The Smithsonian Institution Building (SIB), familiarly known as “the Castle”, is a 10,200 square meter (110,000 square foot) building located on the National Mall in Washington, DC. It was designed by James Renwick, Jr., under the direction of the Smithsonian’s first Secretary, Joseph Henry, and the Board of Regents. When completed in 1855, the building housed all the Smithsonian’s operations including research and administrative offices, lecture and exhibition halls, a library and reading room, chemical laboratories, storage areas for specimens, and living quarters for Joseph Henry and his family. As each successive Secretary has redefined the Smithsonian’s mission and managed its growth, the Castle’s interior spaces have undergone many modifications. While the building's stewards do their best to maintain and repair it, continuing decay and piecemeal remodeling threaten the integrity of the building.  In order to prevent impending catastrophic failure of structural, environmental, mechanical, and electrical systems, the building needs a full system revitalization.

The last major renovation of the Castle, including upgrade of HVAC, electrical and plumbing systems, was completed more than fifty years ago, in 1968. With the exception of its East Wing, the Castle’s exterior of Seneca sandstone has remained largely unchanged. In order to provide a world-class visitor center and executive office setting, all building elements and systems require replacement or restoration. This includes windows, roof, exterior stonework, mechanical, electrical, plumbing systems, life safety security and information technology systems. The Central Utility Plant will be essential to provide mechanical and electrical infrastructure support. 


Goals of the Castle revitalization will include:

  • Installation of efficient building systems
  • Provision of state-of-the-art visitor services and amenities
  • Restoration of building exterior
  • Mitigation of blast and seismic vulnerability
  • Revitalization of iconic building for a century of further use


Smithsonian Institution Building (the Castle)

Photo of the Smithsonian Castle


  • Inclusion of Interior Work in Section 106 Consultation on the RoHC Revitalize Castle

    The Smithsonian, National Capital Planning Commission (NCPC), and Advisory Council on Historic Preservation have concluded discussions on the inclusion of the review of interior work in Section 106 consultation on the RoHC Revitalize Castle. The legal concept is whether the interior and exterior components of the project have “independent utility” from one another, or do they only work together. The decision is that certain connected interior and exterior changes should be part of Section 106 consultation. Smithsonian and NCPC agree that exterior actions with associated interior actions will be included in Section 106 consultation on this project to fulfill our collective Section 106 obligations.  

    Click here to download the memo.

  • Telecommunications Hub Relocation 
  • A critical first step for the RoHC Revitalize Castle project is the relocation of a telecommunications hub currently in the basement of Castle. The telecommunications hub supports all of the South Mall Campus buildings, the National Air and Space Museum, and the National Museum of the American Indian. Relocation of the telecommunications hub must be complete prior to beginning construction work on the Castle, and was submitted separately to the District of Columbia State Historic Preservation Office (DC SHPO), Commission of Fine Arts, and the National Capital Planning Commission. The SI proposed a “determination of no adverse effect” for relocating the telecommunications hub to the National Museum of the American Indian, and the DC SHPO concurred in the determination. Project documentation and the Section 106 determination are shared with Consulting Parties in accordance with Stipulation 2.C.ii of the Programmatic Agreement for the South Mall Campus Master Plan.

         Click here to download project documentation for the relocation of the telecommunications hub.

General inquiries can be sent to the project email address below:



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