Kennedy
Kennedy—This name in N.E. Ulster is of Scottish origin, in Gaelic Mac Ceanadaidh, according to Dr. McBain, who derives it from the Irish Ceinneidigh, ugly head.
This Scottish sept belonged to Ayrshire, the North part of Galloway, and the name is found in Argyle and Inverness. The McKennedys were formerly Lords of Bargany in Ayr. and Earls of Carrick. The family name of the Earls of Casselis was Kennedy. William Buchanan says the McKennedys were originally descended from the once potent surname "of the Mac Kennedys of Ireland."
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees