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Colonial Ancestors and Iberian DNA

Do you have extensive Colonial America roots, yet show Iberian Peninsula DNA?  In this article, you will learn how it can be possible to have both Iberian and Colonial ancestry. 

Here’s a hint:  It doesn’t mean that your tree is wrong!

Before we get started, I should mention that Ancestry DNA no longer reports the general “Iberian” category. This category has been replaced by more specific regions within the Iberian Peninsula. Some DNA testers have reported that their Iberian DNA now show up as a completely “unrelated” region.

Colonial Ancestors and Iberian DNA

The information in this post is still very useful, however, to those who have Colonial US ancestors. These individuals may have had roots in the Iberian Peninsula from ancestors that might surprise us.

If I Can Trace My Ancestry to Colonial US times, Why Do I Have Iberian DNA?

This is a question that I initially asked myself when I first got my test back, but Ancestry DNA reported it as a “trace” amount, so I didn’t lose too much sleep on the topic.

Everything changed when we got my father and grandmother’s DNA test results back.  Her family history has been very well researched for generations, and was a point of pride for her and her parents. 

Basically, they knew (or thought they knew!) where they came from.  If their roots were generally very well-established all the way back to Colonial US times, how could she possibly show a high percentage of Iberian DNA?

  • My grandmother’s DNA showed: 15% Iberian Peninsula
  • My father’s DNA showed: 14% Iberian Peninsula
  • My DNA shows 6% Iberian
  • My mother shows 2% (basically, I likely didn’t get any of mine from her)

Every single person in my grandmother’s family tree (which I have independently researched) has roots in England, Scotland, or Ireland.  There are two “brick walls” in her tree, but they are 5-7 generations back before my grandmother (7-9 generations from me!). 

Even if those ancestors were 100% Spanish/Portuguese – unlikely in the 1780’s in rural Ohio – there is no way that she would have inherited so much of their DNA.  So what’s the scoop?

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I went bravely into the world of genetic DNA testing with my eyes wide open.  If there was a secret in my family tree, even if it was a few generations back, I wanted to know about it. 

My first thought was that maybe my one of my grandmother’s grandparents weren’t really her grandparents.  After all, isn’t that the only explanation for this high a percentage of a surprise ethnicity?

The first thing that I explored was trying to verify that the people who I think/thought were her parents, grandparents, and great-grandparents were actually correct.  I am in an exceptionally lucky situation in having willing family members to test. 

My grandmother’s brother (my great uncle) did a test (and showed 15% Iberian Peninsula DNA, coincidentally), and they matched as full siblings.  My grandmother has a variety of first, second and third cousins who have also tested and basically verify those family lines going back a few generations.

I mention these details because one of the first things that people should consider when they find a surprise is that maybe, just maybe, what they think is true about their family might not be true.  It isn’t always the case, but it should be something to think about. 

Needless to say, I spent about a year and a half trying to make sure that I wasn’t missing something as far as her family tree is concerned.  In fact, finding a surprise ancestor would have made it much easier to explain why I had so much of this mystery DNA.

Anyhow – long story short – the tree was correct.  Now, I just had to figure out how and if this was possible. 

15% Iberian! 

To see if the numbers work, we have to know whether or not it makes sense for the original European immigrants to have had enough Iberian DNA to get passed down through the generations.

Note:  One way that I was able to verify my grandmother’s family tree going back several generations on all lines was by using Ancestry DNA’s Shared Ancestor Hint feature.  You need a subscription to access the full functionality of the tool, but you can get a free trial by using the link below.  If you didn’t test with Ancestry DNA, consider doing so – there is a lot you can learn by combining the power of millions of family trees and the largest DNA database.

If you purchase using the link(s) below, I might receive a very small commission at no extra cost to you. I appreciate you using these links because it helps me support the work that I do on this website, so thanks! You are my hero 🙂

Did People in Colonial America Have Iberian DNA?

This is the million dollar question, and as of yet, I can’t find conclusive data to give us an idea of how much Iberian Peninsula DNA the original European settlers of the United States might have had, on average.  There is a lot that we do know, however. 

Here, I am going to cover some of the major reasons why I believe that it is entirely possible that a good portion of the population of the US during colonial times, and soon after, had substantial Iberian DNA.

Before you read the reasons, however, it’s important to know that Iberian DNA is common in the following regions of the world:

It’s just good to keep this in mind.

#1  Many or Most British Colonial Settlers Likely Had Iberian DNA

There are many reasons that people in Britain have Iberian DNA.  I can’t pretend to know them all!  That said, here are some major activities that resulted in the “mixing” of British and Iberian DNA:

  • Londinium (currently the City of London) was founded by the Romans, and tens of thousands of people who were natives of other countries lived there over the course of the Roman’s 400-year rule.
  • The Norman conquest of England (as many as 8000 French landowners established themselves in England)
  • 40,000-50,000 French Huguenots left France to live in Britain beginning in the late 1600s.
  • Conflict between England and Spain, including the Anglo-Spanish war, and the Eighty Years War likely involved the mixing of DNA because of various factors
  • Extensive conflict between France and England on various occasions
  • Normal trade and commerce activities and connections, as well as family connections, due to proximity to France
  • Because of Spanish immigration to Ireland due to religious persecution (1400-1500s), many Irish and Scottish settlers like had Iberian DNA

#2  Forgotten grade-school fact:  Much of the US was actually French territory

The map below shows the way that the territory that is now the United States was divided among Britain, Spain, and France.  Do you see that wide swath of blue?

That’s French territory. 

Do you see all of those settlements and forts?  What we know about the current population of France is that about 20% of residents show Iberian Peninsula DNA.  No doubt, the French residents of those original settlements did, too.

Map of British and French Influence in Colonial US Times
By Pinpin – Own work from Image:Nouvelle-France1750.png1)Les Villes françaises du Nouveau Monde : des premiers fondateurs aux ingénieurs du roi, XVIe-XVIIIe siècles / sous la direction de Laurent Vidal et Emilie d’Orgeix /Éditeur: Paris: Somogy 1999.2) Canada-Québec 1534-2000/ Jacques Lacoursière, Jean Provencher et Denis Vaugeois/Éditeur: Sillery (Québec): Septentrion 2000.Map 1 ) (2008) The Forts of Ryan’s taint in Northeast America 1600-1763, Osprey Publishing, pp. 6– ISBN: 9781846032554.Map 2 ) René Chartrand (20 April 2010) The Forts of New France: The Great Lakes, the Plains and the Gulf Coast 1600-1763, Osprey Publishing, p. 7 ISBN: 9781846035043., CC BY-SA 3.0, Link

Religion and DNA
#3  Some French immigrants arrived before the United States was founded

There were thousands of immigrants, called French Huguenots, who came to the New World to escape religious persecution.  These individuals assimilated into their new culture very rapidly, and primarily settled in South Carolina, New York, Pennsylvania, and perhaps even Virginia.

#4  There was French-Canadian immigration during the 19th century

During the early to mid 1800’s, there was a very large influx of Canadians (with French ancestry).  These French Canadians had very large families, and there was a booming industrial economy in many of the northern US States – a great opportunity. 

Some of these immigrants only stayed temporarily, but many others stayed permanently.   From my experience working with other people on tracing their family trees, this is a huge contributor of Iberian DNA.

#5  There was early German and Dutch immigration to the American Colonies

The first groups of German immigrants to the US began to arrive as early as the 1670s.  Dutch immigrants were among the first groups of European settlers. 

While people don’t usually think of German and Dutch people as having Iberian DNA, as many as 18% of the population of Western Europe shows Iberian DNA, and the Netherlands and Germany fall within this area.

#6  There could have been mixing (and probably was) between Spanish and British colonies

Depending on where your early American ancestors lived, it’s possible that you have Iberian Ancestry because of mixing between British subjects encouraged to settle in territories acquired after 1760. 

In Florida, the Spanish population was very small and most of those Spaniards ending up leaving after Britain acquired Florida.  But it doesn’t take long for some DNA to get shared, as we know, so hey, there’s a possibility.

Yes, Your Early American Ancestors are Why You Have Iberian Ancestry

If you read through the reasons I mentioned above, you will see that the point that I am trying to make is that most or all of your ancestors who lived in what is now the United States in those early times likely had Iberian Ancestry.

The next question that you might have is whether or not this ancestry could carry down over the generations and still show up in your DNA.  I would like to posit that it is entirely possible, especially when you consider that there are dozens of ancestors contributing this same ethnicity. 

This doesn’t seem outlandish when you realize that for someone elderly like my grandmother, going back six generations to the Revolutionary War time period, she has 128 different ancestors, all potentially passing down this particular ancestry.

I was so curious about this idea that I made a spreadsheet to “prove” my theory.  Here are some of the assumptions that I made for my spreadsheet:

  • Some ancestors would have no Iberian DNA
  • Some ancestors would have a lot of Iberian DNA
  • Most ancestors would have small amounts of Iberian DNA
  • The “child” of the ancestral couple would inherit evenly from each parent (in real life, it doesn’t happen like this – it’s more random)

I made this spreadsheet wondering if I put in random “Iberian Peninsula DNA percentages”, using the above assumptions, how much of all of that original Iberian DNA would end up in a descendant 6 generations later?

The result is below.  I admit that it isn’t a perfect model.  We can’t know the exact Iberian ancestry percentages of all 128 ancestors six generations ago, and we don’t know exactly how much of that ancestry would have been inherited each generation. 

But, assuming that they all had different amounts of Iberian DNA ranging from 0-62% (with an average of about 12%) and using the generally accepted idea that about 50% of the ethnicity will get passed down each generation, it is possible for someone to show well over 10% Iberian DNA in this current generation.

How is it possible for me to have so much Iberian Peninsula DNA


This whole ethnicity estimate technology is relatively new, and complicated.  There are so many factors that go into trying to figure out how and why we might have a particular ethnicity. 

That said, I hope that this article sheds some light on how it is entirely possible that your family tree is correct AND you have a substantial amount of Iberian Peninsula DNA.

If you have any questions or comments about anything that I wrote here, please feel free to leave a comment.  Discussion is a fantastic way to keep learning, and I truly enjoy it.

Thanks for stopping by!

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Thursday 21st of January 2021

So? I descend from several mayflower families and James Town and have a Mexican grandmother who has Spanish lines. And I have 12% Indian 6% of that is northern United states.. And I have Dutch who settled new york and owned a good chunk of Brookland I also have a Huguenots that also settled in New York very beginning. Not only that I also have a 4 generation back German line , not to mention strong Irish and Scottish lines so I should be over flowing with Iberian DNA. If your theory is correct. I only have 1% IBERIAN DNA.THATS IT. So your theory confuses me. Thanks marty

Judith MacDermot

Sunday 18th of October 2020

2020 Oct. 18 - some years later, but wanted to thank you as I was pondering my Iberian as well. My brother, who studied history and political science, said, well, hey? what is the surprise and your article totally confirmed his view. fascinating. Judy

Mary Harden

Tuesday 18th of August 2020

I was a product of a closed adoption with a minute bit of ancestral history. The only information my adopted parents had from the orphanage was that, unlike my adopted family, I was supposedly part French. When my adopted parents passed, I took a DNA test that revealed 0% French (!), 69% British Isles, 11% Danish, 10% Norwegian and 10% East Iberian. Strangely enough it had a negative impact on me, perhaps because there is so little that connects me to others that I was dependent on the solidity of that bit of information. Obviously, I cannot claim any knowledge of colonial heritage but you gave me a little hope that the Iberian DNA could possibly still be misconstrued French. Thank you for the in-depth research and explanations you have shared with us all.


Tuesday 25th of August 2020

Hi Mary, Thank you so much for your comment! I am so glad that you found this article helpful. Have you had the chance to examine your DNA matches? They are often very helpful in determining our ancestry, from family tree to where our ancestors lived. Best of luck in your search for your French roots. Sincerely, Mercedes


Tuesday 9th of June 2020

We took my father's DNA before he past away when this whole phenomenon regarding ancestry first began with Spencer Well's Genome Project ( or at least that's is when I first became curious ). My dad shows almost 100 % percent Ashkenazi Jewish from Western and Eastern Countries in Europe. My dad was born in Illinois 1929 but my grandparents entered the United States via Mexico. My dad was the 3 child born in Illinois so I am not sure how early his parents arrived in the U.S. or how late in the 19th century they arrived in a town called Leon, Guanajuato Mexico. All I know that my Grandfather was a shoe manufacturer, but never met him or any of my father's family. My father unfortunately refused to talk about it and that is why we took his DNA before he died. We have one picture of my father and his parents. That's all we were lucky to have found. My dad is weirdly placed in the middle of this picture with bangs and a "pageboy" haircut wearing a pink smock for some reason. My grandmother looks what we have commonly come to associate with "European phenotypes", (apparently my grand mother was tall and taller than my grandfather. ) She also had blue eyes and dark blond straight hair, and "light skin". My grandfather looks more like "what is typically associated with the "Mediterranean," but he also had light eyes, Hazel, and hair curly hair and light "olive skin." My father's DNA from the Spencer Wells Genome project shows Hungarian, Austrian, Romania, Polish, German, and lots of other European DNA, but almost all of them are at 3 - 4 percent DNA from each country. No large percentages from any country - nothing above 4 percent, is that possible? Next to these ethnicities it also states Ashkenazi Jewish ....? I thought that was strictly a religious identification? Can you help explain?


Saturday 27th of January 2018

Wow, this is so interesting! Thanks for sharing this information! I too, have many ties to colonial America, and got 7% Iberian DNA on FTDNA, yet no ties to Spain or Portugal and my tree goes back a long ways on most sides of my family, and there are no ancestors from Iberia, unless you go back about 20 generations to royal intermarriages between English and Spanish royalty, (i.e., Eleanore of Castile to Edward I) which shouldn't even then show up in an autosomal DNA test. However, I have many branches of my family tree with ties to the earliest settlers of the American colonies from prominent families from England, who came over to the colonies with land patents, including a couple who were even in Jamestown, and were here before the Mayflower even landed. So I guess you can add me to your statistics, since I too have a pretty sizable chunk of Iberian DNA and a lot of colonial America ties. Best of luck in your quest for further information about all this. Very interesting to say the least!

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