I know that george bush and his father were presidents, as well as John Adams (I think), is there any president of the USA who was biologically related to 2 or more other presidents?


Obviously at some level it's a degenerate question, because ultimately every human on earth is related.

So given that we are really good at genealogy these days, it probably shouldn't be surprising that there are oodles of them that we know of.

Looking over the link provided by Lars in the comments, it looks like the closest related triple were Madison, Polk, and Taylor who were second cousins (once removed in the case of Taylor and Polk).

Even Obama has known relation to three other presidents. James Madison was his third cousin9, LBJ his fourth3, and Carter his eighth2.

Going past that, frankly It would be much easier easier to list those who don't have two known relations. Those are (listed in order with presidency number):

  • 1 Washington
  • 3 Jefferson
  • 5 Monroe*
  • 7 Jackson
  • 13 Filmore
  • 15 Buchanan
  • 17 A. Johnson
  • 21 Arthur
  • 28 Wilson
  • 34 Eisenhower
  • 35 Kennedy
  • 36 LBJ*
  • 40 Reagan
  • 42 Clinton

You might notice that the pace slows down towards the end. That makes a certain amount of sense, as the genealogical fan-in increases as you move down generations.

Still, that's only 14 of the 45 Presidents.

* - Related to one other POTUS, but not two

Numeric Superscripts designate level of removal

  • Not sure I got this list 100% correct (as there was a lot of data to reconcile), so wouldn't mind some backstopping. But It should be close. – T.E.D. Jun 26 '19 at 14:05
  • If you read Lars's links more closely, you will see that if you count relationships by marriage you can certainly remove Jefferson and Wilson from that list (combining with the next comment to get the 3rd relation). If it doesn't have to be a presidential marriage, but a relative of one who married a relative of the other, then you can also remove Eisenhower. – C Monsour Jun 27 '19 at 3:08
  • 1
    Also, if you allow very distant cousins, you can remove Washington, Jefferson, and Monroe, based on common descent from Edward III. – C Monsour Jun 27 '19 at 3:09
  • @CMonsour - In the absence of a question clarification otherwise, I made the decision, in this answer at least, not to include relationships by marriage (although it would make things much simpler, as it would make all relationships transitive). Its possible I screwed that up early on in the list though, which is one of the reasons I appreciate double-checking. – T.E.D. Jun 27 '19 at 13:53
  • You still probably ought to delete Washington, Jefferson, and Monroe, as they have an identifiable common ancestor from the 1300s. – C Monsour Jun 27 '19 at 20:38

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