Indirect relatives
This is a list of some of the closer blood relations, other than direct descent, between U.S. Presidents. (See Cousin chart to understand the terms used here.)
Third cousins
James Madison and Barack Obama (nine times removed)
Fourth cousins
Lyndon Johnson and Barack Obama (three times removed)
Seventh cousins
Harry Truman and Barack Obama (three times removed)
Eighth cousins
Jimmy Carter and Barack Obama (twice removed)
Tenth cousins
Gerald Ford and Barack Obama (once removed)
George H.W. Bush and Barack Obama (once removed)
Eleventh cousins
George W. Bush and Barack Obama
Presidents related to British royalty
Barack Obama (descendant of Edward I of England and William the Lion of Scotland)
As a result, all of the listed people are direct descendants of Alfred the Great. All but two of them are also descended from William the Conqueror with the exceptions of Rutherford Hayes and Warren Harding. Most of these royal ancestors were born before the Black Death killed much of the population of Britain in 1349.
See also
Notable relatives of Barack Obama - http://en.wikipedia.org/wiki/Family_of_Barack_Obama#More_distant_ge...
Source: Genealogical relationships of Presidents of the United States
http://en.wikipedia.org/wiki/Genealogical_relationships_of_Presiden...
