Historical-Boundaries Atlas

Summary

This article traces the development of historical-boundaries atlases from early twentieth-century printed maps to national historical geographic information systems. Created to reconstruct changing administrative and electoral jurisdictions and to support statistical mapping, early U.S. atlases combined cartographic evidence with legal boundary descriptions, especially for counties and congressional districts. Later projects drew on session laws, census materials, population statistics, and digital cartography to document boundary changes systematically. From the 1990s onward, GIS transformed these efforts into topologically structured, searchable boundary files linked to historical data. Major initiatives—including the Newberry Library’s Atlas of Historical County Boundaries and historical GIS projects in Great Britain, the United States, and China—expanded geographic and chronological coverage. Historical-boundaries atlases thus evolved into essential research infrastructures for interpreting records, mapping demographic change, and analyzing past administrative geographies.