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Irish DNA in Mexico?

If you have Mexican ancestry and took a DNA test, were you surprised to see Irish on your results?  In this post, learn how common this is, and how you may have inherited DNA from this region of the world.

Irish DNA in Mexico

There is a lot of misinformation out there about the “typical” genetic makeup of the average person from Mexico.  In fact, most people expect to find only “Spanish” and Native American ancestry, and are shocked to know that it’s really common to find signs of Irish ancestors tucked within your DNA.

In this post, you’ll learn:

  • How much Irish DNA the average Mexican might have
  • How Irish DNA might have ended up in your genes
  • How to get started tracing your Mexican (and Irish!) roots

How much Irish DNA does the average Mexican have?

If you have Mexican roots, and you do a DNA test, should you expect to find Irish DNA?  And if so, how much Irish DNA is “normal” for a person from Mexico?  As it turns out, there is no “right” answer.  You can have a lot of Irish, or just a little bit of Irish, and be from Mexico. 

I’ve seen people from Mexico show 1% Irish, and 15% Irish, but I would no longer be surprised to see results for someone with even more Irish ancestry.  And of course, if you have one parent born in Mexico, and another born in the US, you could have inherited Irish from both of them, just like my daughter did.  She has 12% Irish, while I only have 9% Irish.

My interest in this topic began when my husband and I opened up his DNA results.  He was born in Mexico in a well-known village that is known for its indigenous roots.  He speaks Nahuatl, one of more than one hundred indigenous languages spoken in the country and can see Popocatepetl from his parents’ home. 

The reason that he wanted to do a DNA test is because he’s significantly taller that most of the people from his town, and when his beard grows out, it is speckled with bright red hairs.  We had always joked about the red hair and height being from a distant Spanish soldier, or something like that, but to be honest, we had no idea what to expect when we opened up his results.

Imagine our surprise when his highest European ethnicity was Irish!  My husband came back with basically Native American, Central Asian, and Irish ancestry. 

He showed less than 1% Iberian (which probably is Spanish), and 1% Italy or Greece (which now shows up as Europe South on Ancestry DNA).  While his Irish ancestry only showed to be about 4%, it definitely sparked his curiosity.  And that’s great, since I definitely need his help to research his Mexican family tree.

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How did I get Irish DNA from my Mexican ancestors?

Many people are surprised to learn that there really is no such thing as a “Mexican DNA”.  Instead, Mexico is a really diverse country with people with ancestry from all over the world, along with indigenous Native American roots. 

Some of this diversity came from Ireland.  While there are some big differences between Ireland and Mexico, the two countries actually have a lot more in common than you might think.  Both countries are majority Catholic, and have a strong system of family values, just to name a few similarities.

We all know the basic story of the Spanish conquest of Mexico, which is why most people think that Mexican DNA should show a basic “mix” of Spanish and Native American DNA.  Real Mexican history is much, much more complicated than the idea that Spanish solders went to Mexico 500 years ago, defeated the Aztec Empire, had babies with indigenous women, and  then went home. 

Many of the Spanish stayed, and Spanish immigration to Mexico has continued since those early days.  Even less known is that Mexico has been a top destination for immigrants from dozens of countries for centuries.  All of this genetic diversity has made for some interesting DNA results for the modern-day Mexican, or person of Mexican descent.

How did you get your Irish DNA?  While I can’t tell you for sure without researching your unique family tree, here are some major events and details that might explain how Irish DNA ended up in your genes:

Irish families fleeing the fallout from the Mexican-American war

There were numerous Mexican-Irish communities that had been established in Mexican Texas, now American Texas.  Many of these Irish communities sided with the Mexican side during the Mexican-American war.  When the war was over, many of these people fled Texas and moved south into the interior of Mexico.

Irish battalion defected from USA Army

Saint Patrick’s Battalion defected from the US Army, likely noticing the injustice that was occurring, and also feeling sympathy for the Catholics experiencing aggression from the Protestant invaders, which was something with which the Irish were familiar.  Sadly, many of these Irishmen were hung by the US Army, but many were able to escape to Mexico.

Discrimination against Irish immigrants in the United States

During the latter half of the 19th century, many Irish immigrants experienced discrimination and violence, and decided to leave the United States and move to Mexico.

Descendants of Irish immigrants to Spain went to Mexico

Some Irishmen left Ireland to live in Spain and fight for the Spanish military during the 1600-1700’s for various reasons, and many of these Irishmen or their descendants, eventually wound up in Mexico

Direct immigration from Ireland to Mexico

During the Great Potato famine of Ireland, which caused many Irish to leave Ireland and go to the United States. Later on, other Irish families still struggling with poverty believed that religion was an important factor in finding a new place to settle, and chose Catholic Mexico.

The image below is from the 1930 Mexican National Census in Monterrey, Monterrey, Nuevo León. The record shows two Irish immigrants, John and Anna Graham, living in the area, as well as many other immigrants from the United States and England.

“Irlanda” is the Spanish word for Ireland. The red arrow indicates where John and Anna reported their place of birth as Ireland. John was born about 1878 and Anna about 1880.

Other reasons

There have been many other smaller instances of Irish immigration to Mexico, or other ways in which an Irish ancestor happened into a Mexican family tree.  If you have any examples of something that you learned in your own family tree research, I would love to hear from you in the comments at the end of this post.

How to get started finding out if tracing your Irish-Mexican ancestry

If you are interested in finding out if you have Irish-Mexican roots, the first thing that I would recommend that you do is take the Ancestry DNA test.  This test is the best for people with Mexican heritage, because they also test for more than 400 Indigenous or Native American regions, many of which are also found in Mexico.

The DNA test will tell you if you have inherited any DNA from Irish ancestors, as well as test you for many other ethnicities.  You can learn more about autosomal DNA testing here:

Another really neat aspect of DNA testing is that you will also get hundreds, or maybe even thousands of DNA matches.  Some of your DNA matches might be relatively close cousins who know a lot more about your family’s history than you do, or even have old photographs and documents that they might be willing to share with you. 

In fact, some of them might even know who your Irish ancestors are based on old family stories.

While you are waiting for your results to come, or if you already took a DNA test, you might be interested in tracing your family tree to see what you can learn, and to see if you can actually find the names of your Irish ancestors.  Follow these steps to get started on your tree:

  • I recommend building a tree on Ancestry, since it’s free
  • Talk to your parents, grandparents, aunts and uncles about your family history.  Try to see if they can give you names and dates of birth of their parents, their grandparents, and great-grandparents.  Anything that they can tell you will be helpful.
  • Try to locate your most recent Mexican ancestors on the Mexican Federal Census (1930)

Even though you don’t need a subscription to Ancestry to build your tree, you will find that it is much easier to get access to really good records and documents if you have a subscription. 


I hope that this post helped you understand a little bit about how common it is to find Irish DNA in your DNA results if you have Mexican roots.  If you have any questions about anything that you read here, or would like to share your own story of Irish Mexican DNA, I would love to hear from you in the comments below.

Thanks for stopping by!

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Wednesday 12th of August 2020

Hi, I've researched my mom's family history and have not stumbled upon any Irish ancestors yet to explain those DNA matches. We weren't anywhere near places mentioned in the article although it is interesting to see this article. I have wondered if some of it is from Catholic priests. With there being Celts in the Iberian Peninsula that may turn up to be an explanation someday. Happy to see your husband has the same ? about his results.


Thursday 13th of August 2020

Thank you for your comment!! I wish you the best of luck discovering the source of your Irish roots.

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