The New England Historic Genealogical Society said Mr Obama’s mother, Stanley Ann Dunham, and Mr Brown’s mother, Judith Ann Rugg, both descend from Richard Singletary of Haverhill, Massachusetts.
‘I think it’s a really interesting thing, where you have the separation between a Democrat and a Republican, but you have one link,’ said David Allen Lambert, the society genealogist who co-discovered the connection with colleague Chris Child.
Mr Lambert said the work had been aided by prior research about Mr Obama, as well as Mr Brown’s cooperation with the society when researchers first contacted him in December.
In 2008, the society discovered that Mr Obama is related to seven prior presidents, including George H. W. Bush, George W. Bush, Jimmy Carter, Gerald Ford, Lyndon Johnson, Harry S. Truman and James Madison. They also learned he was related to Brad Pitt, the Hollywood actor.