Ancestor fall off the map? Use this FREE Chrome extension for Ancestry and FamilySearch to help find them!

It’s been a long time in the making…so I’m excited to finally make this Chrome extension available!  Here’s a run-down on what the Chrome* extension does and why it’s important for your searches on Ancestry and FamilySearch.

Are you unknowingly sabotaging your searches on Ancestry and FamilySearch?

When searching on, don’t be lulled into complacency by the convenient “City, County, State…” autocomplete dropdown menus like this one:

Searching in Denver County for James Smith b1850 in 1880 US Census on Ancestry

Why?  Because the county listed in the drop-down may not be right!  The county may not have existed in the year you are searching…or boundaries may have changed.  (Keep reading…county boundaries have changed over 17,600 times in the U.S.!)  How can you know if this is a problem you’re facing?

SOLUTION:  The new Historical U.S. Counties Auto-Checker Chrome extension will automatically alert you as you type a place and year.  In the example below, see the warning that Denver County did not exist in 1880!


You can then click the MAP link to determine exactly what County you SHOULD be searching in for the year you are searching.  The map will open in a new browser tab, center on the State you are searching and the historic boundaries for the year you are searching will draw.  Click around the map to explore or use the Search Places box above the map to go directly to a city, such as Denver, CO in this example:

SO, Denver was located in Arapahoe County, Colorado in 1880!

Why does this matter?  Let’s find out:

Search results for James Smith born 1850 in Denver using only Ancestry’s autocomplete dropdown (where is he?!?):

Using the information from the MAP link in the Historical U.S. Counties Auto-Checker Chrome extension, now go back and edit your search to the CORRECT county (Ancestry’s autocomplete may not show you a hint for “Denver, Arapahoe County…” but be stubborn and type it anyway!):

Search for James Smith in Denver, Arapahoe County in 1880

The Historical U.S. Counties Auto-Checker Chrome extension now tells you that Arapahoe County is a valid county, formed in 1861 and its boundaries changed 2x between formation and 1880.  (If you’re curious and want to see the boundary changes, just click the MAP link).

Now, click Search and your new results appear (there he is!):

So James Smith born about 1850 DOES reside in Denver in 1880!  We just needed to know Denver was part of Arapahoe County in 1880!

How many times has not knowing the correct county kept you from finding a record for your ancestors?

Probably more that you thought:  U.S. county boundaries have changed over 17,600 times since America was settled in colonial times.  Don’t sabotage your search for ancestors by not knowing the correct county for the historical year you are researching.

Search with confidence:  The Historical U.S. Counties Auto-Checker Chrome extension makes use of the award-winning Research Hub’s Historical U.S. Counties on Google Maps tool, underpinned with the complete dataset of the authoritative Newberry Atlas of Historical County Boundaries.

With the Historical U.S. Counties Auto-Checker Chrome extension, now you can easily know about county search errors and explore county boundary changes.  And with that knowledge you may very well find new records that were “hidden” on Ancestry or FamilySearch all along!

Installation Instructions

Install at

Click the “Add to Chrome” button to install.  (You may see a standard confirmation window that states that the extension can “Read and change your data on or”.  Rest assured that the Historical U.S. Counties Auto-Checker Chrome extension ONLY reads the place and year fields and shows the county information as shown in the screenshots above; it absolutely DOES NOT make any changes to your data whatsoever.  No logins or email addresses are required to use the extension!)

Instructions are available at both the installation link as well as in a popup that appears when you first install it.  But I think you’ll find it incredibly easy to use, as you don’t have to do anything different than you normally do when searching on Ancestry and FamilySearch…the county information box just automatically appears as you type places and years in all of the search boxes! 

Note, this is the first version of this tool, so if you find any bugs or issues, please contact me on the form on the lower left side of this page.  And if you find it useful, please leave a rating or review on the chrome web store.

Happy searching!

* The Auto-Checker extension supports the following browsers: Google Chrome and Microsoft Edge Chromium

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