# About the Atlas The Atlas of Historical County Boundaries is a comprehensive resource on the creation and evolution of every U.S. county, from the colonial period through 2012. Developed at the Newberry Library in Chicago, it provides maps, chronologies, and metadata documenting every boundary change. ## FAQ ### What is the Atlas of Historical County Boundaries? The Atlas provides maps and documentation of the creation and changes to every county in the fifty U.S. states and the District of Columbia up to 2012. It also covers: - Non-county areas - Unsuccessful authorizations for new counties - Changes in county names and organizations - Temporary attachments of unorganized areas to functioning counties The principal sources are the official session laws of colonies, territories, and states. ### Why does the Atlas stop at 2000 (or 2012)? The Atlas project set out to cover county boundaries from the colonial era through the end of the 20th century. - Work documenting all 50 states was completed in 2010. - The national data files were contributed in 2012. The project is now closed and not being updated with new changes. For more recent data (post-2000), we recommend the NHGIS (National Historical Geographic Information System). ### Can I send you corrections or report errors in the data? We welcome knowing when something looks wrong, but the project itself is no longer being updated. That means we cannot incorporate corrections or edits into the Atlas files. If you discover a likely error, you are still welcome to contact the Newberry Library—we may be able to make note of it for researchers, but it will not change the existing Atlas data. ### Who created the Atlas? The Atlas was developed at the Newberry Library in Chicago, supported by the National Endowment for the Humanities and additional foundations and individuals. - First efforts began in 1975–76, when historians recognized the lack of reliable county boundary maps. - A pilot project produced data for 14 states, published in 1984 as Historical Atlas and Chronology of County Boundaries, 1788–1980. - The full Atlas launched in 1987 and concluded in 2012, with the Hermon Dunlap Smith Center for the History of Cartography at the Newberry maintaining the site. - In the summer of 2025, we rebuilt the site, due to a third-party vendor retiring a critical technological component. ### Why was the Atlas originally created? Historians needed reliable maps of counties in the revolutionary and early national periods, but none existed. The Newberry’s project aimed to build a comprehensive cartographic database of county boundaries, both to serve historical research and to demonstrate the potential of digital cartography (still new at the time). ### How is the data organized? For each state, the Atlas includes: - Boundary change maps - Chronological text descriptions - Metadata in two forms: - A detailed FGDC-compliant document - A one-page summary ### Can I reuse the data? Yes. The Atlas data is released under Creative Commons CC0 1.0 Universal (Public Domain Dedication). You may use it without requesting permission. ### What happened after the Atlas ended? By 2010, the project had documented all 50 states. The final national dataset was released in 2012. No further updates are planned.For ongoing county boundary research or more recent data, consult NHGIS or other contemporary GIS resources. ## Credits ### Original Project (Data Compilation and Historical Research) The foundational historical and geographic data featured on this site was compiled and digitized by a dedicated team over a decade ago. We gratefully acknowledge their contributions: - **John H. Long**: Editor, and Historical Compiler - **Peggy Tuck Sinko**: Assoc. Editor, and Historical Compiler - **Gordon DenBoer**: Historical Compiler - **Emily R. Kelley**: Historical Compiler, and GIS Compiler - **Laura Rico-Beck**: GIS Specialist, and GIS Compiler - **Peter Siczewicz**: GIS Consultant, and Interactive Map-site (ArcIMS) Designer - **Robert Will**: Cartographic Assistant, and Historical Compiler - **John Ford**: Cartographic Assistant, and Historical Compiler - **Kathryn Ford Thorne**: Historical Compiler - **Deborah Skok**: Historical Compiler - **George E. Goodridge, Jr.**: Historical Compiler - **Douglas Knox**: Book Digitizing Director, and GIS Compiler - **Brodie Austin**: Original Website Designer This current version of the website would not be possible without their extensive work in compiling and curating the historical data. ### Current Project Team (Website Rebuild and Redeployment) This updated site was launched in 2025 with a fully reimagined codebase and user experience, while retaining and reorganizing the original dataset to optimize performance and accessibility. - **[Jen Wolfe](https://n3w.srht.site/jen/)**: Project Manager - **[Nicolas White](https://n3w.srht.site/)**: Lead Developer and Data Engineer - **[Parker Otto](https://www.linkedin.com/in/parker-otto/):** Contributing Developer - **[David Weimer](https://www.newberry.org/news/david-weimer-joins-the-newberry-as-curator-of-maps)**: Project Director