The historic Homestead House, on the campus of the Smithsonian’s Environmental Research Center in Edgewater, Maryland, was damaged as a result of the unexpected earthquake of 2011. Preservation standards followed by the Smithsonian Institution call for the careful assessment of the historic character of a building in connection with a condition assessment to set parameters for interventions. Through a team approach using experienced historic preservation architects and a contractor with a long history of quality preservation work, the seismic repairs were undertaken to ensure that the proposed work maximized the retention of historic materials. Standard seismic repair approaches for newer construction with exposed bracing and substantial rebuilding was not appropriate for this structure, which is listed as a historic building by the state of Maryland. There are often conflicts between prescriptive building codes and the performance of historic building materials, and in this case the structural engineers initially were calling for more intense interventions based on conservative assumptions regarding materials. Ultimately, in-situ testing of the existing masonry walls was performed, and the historic building’s structural resistance was found to be sufficient to perform adequately without a more extensive intervention. The overall project and the improvements to the building’s future performance are outlined with examples of sound preservation treatments and approaches. At the time of preparing this report, the building repairs for the exterior restoration and the interior stabilization were recently completed.