McKinley (surname) McKinley (surname) McKinley is a Scottish and Irish surname historically associated with northwestern Ireland's County Donegal, and the over-kingdom of Ulaid in northeastern Ireland and the Scottish Highlands. The McKinley are of the ancient Ulaid race and are a branch of its "Red Branch" MacDunleavy (dynasty) royal house of the Dal Fiatach which dominated the kingship of the over-kingdom of Ulaid (original Gaelic language Mac Duinnshléibhe). Etymology for the origins of the surname proposes that the Anglicized surname McKinley, like the surname MacNulty (Gaelic Mac an Ultaigh, trans. "son of the ultonian, ulidian or ulsterman"), arose originally from a Gaelic
Eolais mac Biobhsach manuscripts going back almost two hundred years. O'Donovan claimed the family name ( "descendent of Eolais") is still found anglicised as "Olus" or "Olis". two instances of the surname corrupted as "Oelase" and "Olase", are found in the Irish Fiants for Leinster. The surname must be very rare. Eolais mac Biobhsach Eolais "mac Biobhsach" (alias " "knowledge", anglicized "Wallis", "Olis" or "Olus" ) was a chieftain of 10th century Gaelic Ireland. He is noted as the first "full chieftain of Conmaicne Réin". His descendants, "the Muintir Eolais", expanded into the territory of present day south county Leitrim, and parts of