Advisory Council on Historic Preservation.

Alliance for Historic Landscape Preservation.

American Association for State and Local History

American Battlefield Protection Program (NPS).

American Planning Association.

The American Institute of Architects (AIA).

The Association for Preservation Technology International (APT): a multidisciplinary organization dedicated to "advancing the application of technology to the conservation of the built environment".

Heritage Preservation Service (NPS).

League of Historic American Theatres.

National Center for Preservation Technology and Training (NPS).

National Conference of State Historic Preservation Officers NCSHPO

National Council for Preservation Education

National Register of Historic Places.

National Register of Historic Places in Pennsylvania..

National Trust for Historic Preservation.

National Trust's Main Street Program.

Pennsylvania Federation of Museums & Historical Organizations.

Philadelphia Athenaeum

Preservation Books (National Trust).

Preservation Magazine (National Trust)

Save America's Treasures.

Secretary of the Interior's Standards for the Treatment of Historic Properties.

Society for American Archaeology

Society of Architectural Historians.

Society for Commercial Architectural.

Sprawlwatch Clearinghouse

State Historic Preservation Legislation Database.

Technical Preservation Services.