How can interpretation be used to promote the sustainable conservation of a historic site? What is meant by sustainable conservation of historic sites is examined and its three aspects: the social, financial, and environmental defined. On the basis of a critical literature review, objectives for an interpretation plan that promotes the sustainability of a historic site are stated. Through case studies, current interpretive practices are examined and evaluated as to their potential for meeting these objectives. Sites chosen for study were identified by heritage professionals as ‘best practices.’ Case studies include Valley Forge National Park, King of Prussia, Pennsylvania; Burton Cotton Gin Museum, Burton, Texas; Strawbery Banke Museum, Portsmouth, New Hampshire; President Lincoln’s Cottage, Washington D.C.; and the National Steel & Iron Heritage Museum, Coatesville, Pennsylvania. Based on the results of case study research, a best practices methodology is developed for writing an interpretation plan with sustainability among its central goals and practical examples of the unique ways in which each site addresses the different aspects of sustainability are given. The methodology developed is tested by outlining an interpretation plan for the Zedler Mill in Luling, Texas that promotes sustainability. This mill was a driving economic force in this small South Central Texas town for a period of nearly ninety years from 1874 to 1964. As with any historic site, conservation of the mill site today and into the future depends upon community support. My findings demonstrate how interpretation programs can provide the community (society) with social and economic benefits that can sustain that support. / text