You’ve probably heard that wild claim that almost every single American president is related to the same English king. It sounds like a conspiracy theory. It sounds like a plot point from a Dan Brown novel. But honestly? It's mostly true.
When we talk about how many presidents are related, the answer usually depends on how far back you’re willing to dig. If you’re looking for brothers or fathers, the list is short. But if you’re looking at distant cousins and shared 12th-century ancestors, the White House starts to look less like a rotating seat of power and more like a very exclusive family reunion.
The King John Connection
Back in 2012, a 12-year-old girl named BridgeAnne d’Avignon made national headlines. She spent months researching over 500,000 names and discovered that 42 out of 43 presidents (at the time) were related to King John of England. He’s the guy who signed the Magna Carta in 1215.
The only outlier back then was Martin Van Buren. He was Dutch. People assumed he didn't fit the "royal" mold. However, further genealogical research by experts like those at the New England Historic Genealogical Society has since suggested that even Van Buren might have a link if you track the lines through Dutch nobility back to the same European roots.
Basically, if you have British or Western European ancestry, there’s a statistically high chance you’re related to King John too. But the concentration of these lineages in the presidency is still pretty striking.
Families That Kept It in the House
Most of us know the obvious ones. The "Father and Son" clubs.
- The Adams Family: John Adams and John Quincy Adams.
- The Bush Family: George H.W. and George W. Bush.
Then you have the "Grandfather-Grandson" duo: William Henry Harrison and Benjamin Harrison. These are the direct links. They’re easy to track. But the connections get way weirder when you look at the Roosevelts.
Teddy Roosevelt and Franklin Delano Roosevelt were fifth cousins. That’s a bit distant, right? Well, it gets more complicated. FDR married Eleanor Roosevelt, who was Teddy’s niece. That made FDR and his wife fifth cousins, once removed. Imagine that Thanksgiving dinner.
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The "Common Ancestor" Web
It’s not just about the big names. Genealogists have found that many presidents who seemingly have nothing in common are actually "cousins" many times over.
- James Madison and Zachary Taylor were second cousins.
- Franklin Delano Roosevelt was reportedly related to 11 other presidents by blood or marriage.
- Barack Obama and George W. Bush are 10th cousins. They share a common ancestor named Samuel Hinkley, who lived in the 1600s.
Why does this happen? Honestly, it’s mostly math. The "Old Stock" Americans—the families that arrived in the 1600s and 1700s—formed a relatively small pool of people. They married each other. They stayed in the same social circles. Over 200 or 300 years, those family trees don't just branch out; they tangle.
Why Does This Keep Happening?
Is it some secret Illuminati thing? Probably not. It’s more about socio-economic inertia. For much of American history, the people with the resources, education, and connections to run for president came from the same handful of established families.
Take the "Gateway Ancestors." These are specific individuals from the colonial era who were already descended from European gentry or royalty. If you can trace your line back to one of them, you’re suddenly "related" to half of the people in the history books.
Genealogist Gary Boyd Roberts, the author of Ancestors of American Presidents, has spent decades proving these links. He notes that while the "royal" connection is common for anyone with New England roots, the sheer density of it among presidents shows how small the American political elite actually was for a long time.
Breaking the Pattern
Lately, the pattern is shifting, but only slightly. Recent presidents have brought in different lineages.
- Donald Trump: Primarily German and Scottish ancestry.
- Joe Biden: Deep Irish roots.
- Barack Obama: Kenyan and English/European (the source of his "royal" link).
Even as the backgrounds become more diverse, the old colonial threads are hard to snap. Because those early families were so prolific, their DNA is everywhere now.
What You Can Do With This Information
If you want to see if you’re part of the "club," you don't need a professional genealogist.
Check your New England or Virginia roots. If your ancestors were in Massachusetts or Virginia before 1700, the odds are very high you’re at least a 10th or 12th cousin to a president.
Search for "Gateway Ancestors." Use sites like WikiTree or American Ancestors to see if your tree hits a name like Thomas Dudley or Anne Hutchinson. These people are the "hubs" of the presidential web.
Look for the "Famous Kin" databases. There are specific tools designed just to cross-reference your tree with the 46 men who have held the office.
Don't get too ego-driven about it, though. If you go back 30 generations, you have over a billion spots on your family tree. Since there weren't even a billion people on Earth back then, we're all just recycling the same ancestors. You’re likely related to a king, a coal miner, and a president all at once.
The next time someone brings up how many presidents are related, you can tell them the truth: almost all of them, but mostly because the "founding" families of America were a much smaller group than we like to imagine.
If you're curious about your own link, start by mapping your great-grandparents. Most people get stuck there, but breaking through that 19th-century wall is where the real history starts to show up. Use the federal census records from 1850 and 1880—they’re the "Rosetta Stone" for American family trees.
Next Steps for You
- Start a tree on a free platform like FamilySearch to see if their "Collaborative Tree" automatically links you to a known historical figure.
- Search for your surnames in the New England Historical and Genealogical Register archives if you suspect colonial ties.
- Map your maternal lines specifically; most people focus on surnames, but the "royal" links often travel through the mother's side in presidential history.