5 Great Sites for County Boundaries

Pretty early on in my research I learned that understanding county boundaries is really important. Read on to learn why.

Why are county boundaries important?

  1. First off, understanding county boundaries helps you know where to look. If you are traveling for original research you will need to know which courthouse has your records. The relevant records will be in the county where they lived at the time the event or transaction took place.
  2. Let’s say you find a marriage record in an online genealogical database in the same state as your person or family of interest, but not in the same town or county. The marriage record does not list the names of the parents. How do you know if the marriage record is for your ancestor?  Well, you will likely need additional information to further support the conclusion that this marriage record applies to your ancestor. But for starters we can assess the likelihood that it does or does not by understanding geography. For example, did the marriage take place in an adjoining county or was it 300 miles away? This simple fact can lend credibility or cast doubt to whether it applies to your ancestor. Again, this alone does not provide “proof,” but it does provide a valuable clue on where to focus your research efforts.
  3. Lastly, you should understand county boundaries because they change! When one stops to think about it, this makes sense. The problem is that most beginning researchers don’t stop to think about it. I certainly didn’t when I first began my research. So, you might think your ancestor moved between the 1850 and 1860 censuses, but it is possible that they didn’t! And looking back at reason #1, your ancestor could have lived in the same farmhouse for decades and yet you will find records pertaining to them in 2 or more counties!

Between kindergarten and 5th grade I attended 4 different schools.  I’ll give you 3 guesses as to why.

  1. No, I was not in a military family.
  2. Wrong, we didn’t move around.
  3. Nope, I wasn’t expelled either (from kindergarten? Give me a break!).

The answer? The school boundaries changed because of incredibly fast growth in my home town of Gilbert, Arizona. We lived in the same house all 5 years, but the boundaries changed. This is very similar to what happened with county jurisdiction boundaries. Boundary changes happened most often as a result of population growth in the area.

Did you know?

The State of Louisiana contains 64 parishes instead of counties!

Where can you learn more?

Illinois County Map
Clickable Illinois County Map from FamilySearch Research Wiki

So, now that you know county boundaries are important, here are 5 great sites that can help you in your research:

  1. Wikipedia.org – Every county in the US has a Wikipedia page. It usually lists when the county was created, from what county(ies) it was created from, adjoining counties, cities, towns, and census places, and usually some brief history.
  2. Mapsofus.org – This site contains interactive maps of county boundaries by state. Each state page contains rotating animated maps showing all of the county boundary changes and all of the county boundaries for each census year for each year.
  3. Newberry Library– Contains an atlas of historical county boundaries, including an animated map showing all state and county formation in the US in 30 seconds.
  4. Genealogyinc.com – Allows you to drill down by state and county to see maps, learn information about them, and for links to resources to find your family history
  5. FamilySearch Research Wiki – Incredible resource for genealogical research. The Research Wiki also includes the ability to drill down by click on the map to find resources for each state and county. (Note: the Research Wiki has pages for countries all around the world. It is not just limited to the United States.)

Please comment and share your favorite sites for county boundary research!

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