The Irish surname McDonnell, also found in Scotland,  is an anglicized form of the Gaelic name Mac Domhnaill meaning “son of Domhnall.” The name is originally chiefly associated with Ulster and specifically Donegal, where the main clan were located, with two further septs in West Clare and Galway, all trace their descent from the same ancestral chief “Domhnall,” meaning “world ruler.” The predominence of the clan dates from the 13th century, and at one point they held over thirteen thousand acres of land in the district of Kilmacrenan, Co Donegal, and were measured amongst the leading land owners in the county.