The Buchanans of Blairlusk & America - http://www.dippam.ac.uk/ied/records/26320
IV. George Buchanan, of Blairlusk, was born in 1648, suceeded his father in 1662, and having sold his estate of Blairlusk to his brother, William, went to Ireland. He settled at Deroran in the County of Tyrone, in 1674, and married in 1675, Elizabeth Mayne, and had four sons: (1) John of Tyrone, ancestor of James Buchanan, H. B. M. Consul at New York from 1816 to 1843; (2) William of Tyrone, from whom the Buchanans of Meadville, Pennsylvania, U.S.A., are said to be descended; (3) George of Munster, from whom the Buchanans of Louisville, Kentucky, U.S.A., are said to be descended; and (4) Thomas of Ramelton in Donegal, said to be the ancestor of James Buchanan, who became President of the United States.