,This application, HistoryQuest DC, is an interactive GIS map that provides historical data on approximately 193,000 extant buildings in Washington, D.C. The map offers several operational layers of information for the user including historic data on individual buildings and historic districts, links to documentation on properties listed in the National Register of Historic Places, information on historic residential subdivisions, and the identification and boundaries of the L’Enfant Plan, and the city’s Squares, and Wards. The featured layer in the map—the Historical Data on DC Buildings—provides information from a variety of sources on original dates of construction, architects, owners and builders of the city’s historic buildings. The application also includes a Query tool that allows the user to analyze the historic data within a specified geographic area or city-wide.This application has evolved out of the DC Historical Building Permits Database, begun in 2002, is on-going. Requests to correct or add new information can be made using the “Propose Data Change” drop-down form located on the banner at the top of the map.,,For questions or concerns, contact the Historic Preservation Office at historic.preservation@dc.gov.,,