This article describes the construction of the Integrated City Sustainability Database (ICSD) that is the first truly comprehensive data set of U.S. municipal government sustainability programs and policies. Taking advantage of a unique opportunity to combine seven independent data collection efforts, it will provide a valuable resource for scholars in multiple disciplines investigating local environmental and energy sustainability. It also adds missing elements to the research infrastructure for the study of local government and urban policy. This nationwide database will provide a comprehensive assessment of municipal sustainability programs that can contribute to a more rigorous and theoretically informed understanding of city government and governance.