The online Atlas of Historical County Boundaries is a go-to resource for determining old U.S. county boundaries.
The atlas of historical county boundaries
How to find county boundaries with the Atlas of Historical County Boundaries in three steps
1. From the Atlas home page, click on the state of interest from the national interactive map.
2. From the state page, click on View Index of Counties and Equivalents. This will show you all current and past county names.
3. From this page, click on your targeted county. You’ll find a timeline of that county’s boundary changes.
Use the timeline to discover what county your ancestors belonged to at any given time. Perhaps you’ll discover you should actually be looking for an ancestor’s marriage record or probate in a parent county, one that existed there before the current county, or in a successor county later carved out of this one.
Google Earth Bonus: The Atlas of Historical Boundary Changes state pages include downloadable maps compatible with Google Earth and Google Maps. If you are not using Google Earth for genealogy yet, watch Lisa Louise Cooke’s free video to see how and why you want to use this amazing 3D map of the world for your family history! You can learn more about downloading the Atlas of Historical County Boundaries files to Google Earth in Lisa’s book The Genealogist’s Google Toolbox.
Learn More about Using Interactive Maps for Genealogy
- Illuminating Time-Lapse Videos Show Our Changing World
- Historical Maps of New York City and More Now Free Online
- Family Maps and Migration Routes Traced with New Tech Tools
This tool puts the excellent Newberry Library historical county boundaries on top of Google Maps:
The Historical U.S. County Boundary Maps interactive tool ( http://randymajors.com/p/maps.html ) shows you the historical county boundaries for any place and historical date you’re researching. See details on when and how the boundaries changed, overlaid on a present-day Google Map.
You can also overlay research locations on the map such as courthouses, cemeteries, churches, and libraries, and link right to them for more information.
While I’m waiting for the Newberry site to come back up, I’ve been using https://www.mapofus.org/ . It’s not as slick, but still very usable and helpful. Halfway down the page, click on the state you want. On the state page, scroll down till you see the map with dates underneath. Click on the date that would be relevant to the time you want, and you’ll see a map with the applicable boundaries!
Thanks, Randy and Christine, for adding your tips to them! Love them!
So glad to hear the site is coming back – thank you Newberry Library – and Lisa for getting us in the loop!