My closest relationship to all of the US Presidents is 5th cousin 5 times removed from Rutherford B Hayes, our 19th president between 1877 and 1881.
My most direct relationships are 10th cousin to George W Bush (43rd), 14th cousin to James Earl Carter (39th), and 16th cousin to Ronald Wilson Reagan (40th).
My furthest relationship is 20th cousin 1 time removed to Franklin Pierce, our 14th president between 1853 and 1857.
I have found blood relationships to all except 5 of the US Presidents. I have yet to find a relationship with John Adams (although I do to his son John Quincy Adams), Andrew Jackson, Martin Van Buren (despite my dutch roots), William McKinley Jr, and Donald Trump.
See my relationships to all of the US Presidents on my space page Wiki Cousins