Unpuzzling Your Ancestors’ County Boundary Changes

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Figuring out your US ancestors’ county boundaries can be like doing a puzzle with pieces that keep changing size and shape.

If one of your ancestral families settled early in what’s now Morrow county in central Ohio, for example, they conceivably could’ve resided in—count ’em up—seven different counties without moving an inch:

Morrow County was formed March 1, 1848, from Crawford, Knox, Marion, Delaware and Richland counties. (A small area went back to Richland County the next year.)
Marion County, formed April 1, 1820, from a “non-county” area that was attached to Delaware County (it remained attached to Delaware County for administrative purposes until 1924)
Delaware County, formed April 1, 1808, from part of Franklin County
Franklin County, formed April 30, 1803, from Ross and a non-county area; it overlapped Wayne county
Ross County, formed Aug. 20, 1798, from Adams, Hamilton and Washington counties
Adams County, formed July 10, 1797, from Hamilton and Washington counties
Hamilton County is one of Ohio’s original counties, formed Jan. 2, 1790, from the Northwest Territory. It expanded in 1792 with more Northwest Territory and Washington County land.

That’s seven different counties that could hold your family’s genealogy records. And this isn’t even the most convoluted example of how counties would annex land, get carved up, change their borders and switch county seats.

Our Unpuzzling County Boundary Changes webinar will show you how to figure out where your ancestor’s records should be during what time periods, using tools such as the Newberry Library’s Atlas of Historical County Boundaries, gazetteers, the Map Guide to the US Federal Censuses, 1790-1820, and more.

The Unpuzzling County Boundary Changes webinar takes place Thursday, Oct. 17, at 7 p.m. ET (6 CT, 5 MT, and 4 PT). Everyone who registers will receive a PDF of the presentation slides and access to view the webinar again as often as you want.

And if you register before Oct. 10, you’ll save $10. Learn more about the Unpuzzling County Boundary Changes webinar here.