What Is A Fourth Cousin?

Large families can be complicated, so you’d be forgiven for getting a little confused about the status of some of your relatives.

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Most of us know that our cousin is our parent’s sibling’s child, but what about down the line? What is a fourth cousin? How many can you have? Read on for more information. 

When you share a set of great-great-great-grandparents, you are fourth cousins.  Or you can understand it by saying your fourth cousin is the child of the brother or sister of your greatest great-grandparent. 

For example, let’s start with Tom and Sue (fictitious characters) 

Tom and Sue have two children – They are siblings 

Tom and Sue have two grandchildren  – They are cousins 

Tom and Sue have two great-grandchildren – They are 2nd cousins 

Tom and Sue have two great-great-grandchildren – They are 3rd cousins 

Tom and Sue have two great-great-great-grandchildren – They are 4th cousins 

As long as the descendants of Tom and Sue are the same amount of generations removed from the same common ancestor, then they will be fourth cousins.

If you have a fourth cousin who came from the brother or sister of your great-great-grandparent who then married the brother or sister of a great-great-grandparent from a different line of the family, then you will have a double-fourth cousin.

What Is A Fourth Cousin?

Double Fourth Cousin 

Double fourth cousins will typically share two sets of great-great-great-grandparents.  In other words, they are fourth cousins – twice. How does it work?

On occasion, two sisters may marry two brothers.  If your great-great-grandfather married the sister of his brother’s wife, then the offspring of the two marriages will be related as a consequence of that marriage and they will be related in two ways. 

Their kids will be double first cousins, their kid’s children will be double-second cousins, and their great-grandchildren will be double third cousins, and their great-great-grandchildren will be double fourth cousins. Complicated? 

Fourth Cousin Once Removed 

A fourth cousin once removed is the son or daughter of your own fourth cousin OR the fourth cousin of your mom or dad. 

When we break the term down, it first means the individual in the cousin relationship who is closest to the older/deceased relative who connects the relationship establishes what degree of cousin you are to each other.

Then, “removed” describes when you share an older/deceased relative with another relative, but you’re not the same number of generations away from that older/deceased relative.

Additionally, if there is more than one generational difference, then it would be twice-removed, three-times removed, etc.

If the relative concerned is a great-great-great-great-great grandchild of the common ancestors, then they are fourth cousins twice-removed. And so it goes on. 

Half Fourth Cousin 

Wait, there’s such a thing as a HALF-fourth cousin? Yes! A half-fourth cousin is your fourth cousin, BUT you two only share one great-great-great grandparent —your half-fourth cousin comes from your great-great grandparent’s half-sibling.

Remember, when it comes to DNA, you’ll share less with your half-fourth cousins than your fourth cousins.

How Many Fourth Cousins Are In My Family?

What Is A Fourth Cousin?

How many fourth cousins you have is different for all families!

The more generations you go back in your family, the more likely you’ll run into people having more children but also more people passing away earlier than they would today. This is simply due to differences in societal norms, public health, etc. between then and now.

If your great-great-great grandparents had lots of children and they all survived and also had lots of children, then you’d probably have a larger number of fourth relatives in your family.

Or, you might have very few fourth-cousins if your great-great-great grandparents did not have many children, and their children did not have many children.

What Does It Mean to be Blood Relatives?

Believe it or not, we don’t always share DNA with people we are related to. According to statistics, you might only share DNA with about half of your fourth cousins! Being genealogically related and DNA/”blood” related are not the same thing.

The statistics get even lower with half-fourth cousins.

Researching your family tree is a great way to, first, figure out WHO your fourth cousins are, and second, get in touch with them!

Researching Family Tree

A good way to discover family information and find out how many fourth cousins you have is to trace your family tree. 

It can be tempting to dive straight in and also look for a specific ancestor, yet this tends to generate a lot of outcomes that can be complicated. So it’s ideal to start on your own and then work backward, locating evidence that links each generation with each other.

With public documents, you can find proof in marriage certificates, birth certifications, as well as wills. 

Talking with people and contacting loved ones can additionally provide clues as well as inevitably your detective work could take you anywhere from neighborhood graveyards and memorials to tape-record workplaces abroad. 

With the right research and a bit of digging, it shouldn’t take you too long to discover who your fourth cousins are. Happy searching! 


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