Old Irish Origin Surnames

This is a list of surnames in which the origin is Old Irish. Old Irish was the form of the Irish language spoken up to the 10th century.
usage
origin
Ó Gallchobhair Irish
Irish Gaelic form of Gallagher.
Ó hAodha Irish
Irish Gaelic form of Hayes 2.
Ó hAonghuis Irish
Irish Gaelic form of Hennessy.
Ó hEachthighearna Irish
Means "descendant of Echthigern" in Irish.
O'Hearn Irish
Anglicized form of Ó hEachthighearna.
O'Kane Irish
Anglicized form of Ó Catháin.
O'Keefe Irish
Variant of Keefe.
Ó Maoil Eoin Irish
Irish Gaelic form of Malone.
Ó Maoil Riain Irish
Means "descendant of a follower of Rian", derived from Irish maol meaning "follower".
Ó Maoilsheachlainn Irish
Means "descendant of Maolsheachlann" in Irish.
Ó Maol Aodha Irish
Means "descendant of a follower of Saint Aodh". It is derived from Irish maol meaning "follower, servant".
Ó Maol Bhréanáin Irish
Means "descendant of a follower of Saint Brendan" in Irish.
Ó Mathghamhna Irish
Irish Gaelic form of Mahoney.
Ó Muircheartach Irish
Irish Gaelic form of Moriarty.
Ó Muireadhaigh Irish
Irish Gaelic form of Murray 2.
Ó Murchadha Irish
Irish Gaelic form of Murphy.
O'Neal Irish
From Irish Ó Néill meaning "descendant of Neil".
O'Neill Irish
Variant of O'Neal.
Ó Néill Irish
Irish Gaelic form of O'Neal.
O'Niall Irish
Variant of O'Neal.
Ó Riagáin Irish
Irish Gaelic form of Reagan.
Ó Riain Irish
Means "descendant of Rian".
Ó Ríoghbhárdáin Irish
Irish Gaelic form of Riordan.
Orman Irish
Anglicized form of Ó Ruaidh.
Ormond Irish
Anglicized form of Ó Ruaidh.
Ormonde Irish
Anglicized form of Ó Ruaidh.
Ó Ruadháin Irish
Means "descendant of Ruadhán" in Irish.
Ó Ruaidh Irish
Means "descendant of Ruadh" in Irish.
Ó Séaghdha Irish
Means "descendant of Séaghdha".
Ó Seanáin Irish
Irish Gaelic form of Shannon.
O'Shea Irish
Anglicized form of Ó Séaghdha.
Ó Taidhg Irish
Irish Gaelic form of Teague 1.
Ó Tíghearnaigh Irish
Irish Gaelic form of Tierney.
O'Toole Irish
Anglicized form of Irish Ó Tuathail meaning "descendant of Túathal".
Ó Treasaigh Irish
Irish Gaelic form of Tracey 2.
Ó Tuathail Irish
Irish Gaelic form of O'Toole.
Quinlan Irish
From Irish Ó Caoindealbháin, which means "descendant of Caoindealbhán", a given name meaning "handsome form" (using a diminutive suffix).
Quinn Irish
Anglicized form of Irish Ó Cuinn meaning "descendant of Conn".
Reagan Irish
Anglicized form of Irish Ó Riagáin meaning "descendant of Riagán". A famous bearer was the American president Ronald Reagan (1911-2004).
Reardon Irish
Variant of Riordan.
Regan Irish
Variant of Reagan.
Riordan Irish
From Irish Ó Ríoghbhárdáin meaning "descendant of Rígbarddán".
Rowan Irish
Anglicized form of Ó Ruadháin.
Ruane Irish
Anglicized form of Ó Ruadháin.
Ryan Irish
Anglicized form of Ó Riain, or else a simplified form of Mulryan.
Shannon Irish
From Irish Ó Seanáin meaning "descendant of Seanán".
Shaw 2 Scottish
From a given name or byname that was derived from Gaelic sitheach meaning "wolf" (Old Irish sídach).
Shea Irish
Anglicized form of Ó Séaghdha.
Sheehy Irish
Variant of McSheehy.
Sheenan Irish
Variant of Shannon.
Slane Irish
Originally indicated a person from Slane, County Meath, Ireland, which is derived from the given name Sláine.
Sweeney Irish
Anglicized form of Mac Suibhne.
Teague 1 Irish
Anglicized form of Irish Ó Taidhg meaning "descendant of Tadhg".
Tierney Irish
From Irish Ó Tíghearnaigh meaning "descendant of Tighearnach".
Tighe Irish
Anglicized form of Ó Taidhg.
Toole Irish
Variant of O'Toole.
Tracey 2 Irish
Anglicized form of Irish Ó Treasaigh meaning "descendant of Treasach".
Treacy Irish
Variant of Tracey 2.
Whalen Irish
Variant of Whelan.
Whelan Irish
Anglicized form of Irish Ó Faoláin meaning "descendant of Faolán".