McAllister (surname) McAllister (surname) McAllister is a surname from Scotland and Ireland that originates from the Gaelic name Mac Alasdair, meaning son of God. Alasdair is the Gaelic form of the first name Alexander. The Mc Alisters for the greater part owe their ancestry to the Scottish clan of the Mac Donalds. The name is derived from the personal name Alexander. The Mc Alisters arrived in Ulster as Gallowglasses at the invitation of the MacDonnell's. Today the greatest numbers of the name are to be found in counties Antrim, Londonderry, Fermanagh, and Dublin, otherwise the name is widely dispersed. The McAllister surname
Mac Aodhagáin Flann Mac Aodhagáin up to the year 1643. The surname has been Anglicised in a variety of ways, including as Mac Egan, Egan, Eagan, Keegan, or Keigan, McKiegan, and McKagan. Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Muirchertach Mac Aodhagáin Mac Aodhagáin Mac Aodhagáin (English: Egan or Keegan), is an Irish Gaelic clan of Brehons who were hereditary lawyers - firstly to the Ó Conchobhair Kings of Connacht, and later to the Burkes of Clanricarde. The earliest surviving Irish law manuscript, "In Senchas Már", was written prior to 1350