About HDP

The Heritage Documentation Programs (HDP) consist of the Historic American Buildings Survey (HABS), Historic American Engineering Record (HAER), and Historic American Landscapes Survey (HALS). The programs document historic sites and structures across the United States through the creation of measured drawings, large-format photographs, and historical reports. Documentation is archived in the HABS/HAER/HALS Collection at the Library of Congress and is available to the public without restriction.

HABS/HAER/HALS documentation comes from a variety of sources, including:

  • donations from academic institutions, members of the public, professional organizations, and state historic preservation offices
  • mitigation completed in conformance with the requirements of the National Historic Preservation Act
  • projects carried out by HDP professional staff
  • competitions overseen by HDP

As authorized under the National Historic Preservation Act, HDP develops and maintains the Secretary of the Interior's Standards and Guidelines for Architectural and Engineering Documentation and program-level documentation guidelines to ensure that all documentation in the HABS/HAER/HALS Collection meets uniform requirements for quality, content, and archival stability.

HDP is part of the National Park Service's Cultural Resources, Partnerships, and Science Directorate.

Learn More about Each Program

  • Drawing of the front facade of the Main Hospital at Ellis Island
    HABS

    Historic American Buildings Survey

  • Drawing of a cutaway section of the Nuclear Ship Savannah
    HAER

    Historic American Engineering Record

  • Drawing of part of the cemetery at Flanders Field in Belgium
    HALS

    Historic American Landscapes Survey

Last updated: September 20, 2023