Historic Preservation Law and Regulations  The work of the DC Historic Preservation Office is guided by two documents -- the Historic Landmark and Historic District Protection Act of 1978 and carried out through the Historic Preservation Regulations (DCMR Title 10A). Historic Landmark and Historic Protection Act of 1978 (DC Law 2-144, as amended)*  Historic Preservation Regulations (DCMR Title 10A)*             * This document is presented in Portable Document Format (PDF). A PDF reader is required for viewing. Download a PDF Reader or Learn More About PDFs.