President Obama's Irish roots

U.S. President Barack Obama with Irish Prime Minister Brian Cowen

The Top Twenty U.S. Presidents Of Irish Ancestry

     1    Andrew Jackson     (both parents born in Ireland)
     2    James Buchanan     (both parents)
     3    Chester Arthur     (father)
     4    Woodrow Wilson   (paternal grandparents)
     5    Grover Cleveland  (maternal grandfather, maternal great-great-grandmother)
     6    Andrew Johnson    (paternal grandfather)
     7    John F. Kennedy   (all eight paternal and maternal great-grandparents)
     8    Benjamin Harrison (two maternal great-grandfathers)
     9    Ronald Reagan (two paternal great-grandparents)
     10  Ulysses Grant (maternal great-grandmother)
     11  William McKinley  (two paternal great-great-grandfathers)
     12  James Polk    (paternal great-great-great-grandfather)
     13  Barack Obama (maternal great-great-great-grandfather)
     14   Richard Nixon (paternal and maternal great-great-great-great-grandparents)
     15  Theodore Roosevelt (maternal great-great-great-great grandparent)
     16  George H. Bush     (at least one Irish ancestor at great-great-great-great-grandparent level and above)
     17  Lyndon Johnson     (Irish-born great-great-great-great-grandparent unconfirmed)
     18  Jimmy Carter (Irish ancestry unconfirmed)
     19   Leslie (Lynch) King     (later Gerald Ford: Irish ancestry unconfirmed)
     20    William (Cassidy) Blythe     (later Bill Clinton: Irish ancestry unconfirmed)