Parent’s name

Casey surname meaning

An Irish patronymic surname from Ó Cathasaigh, “descendant of Cathasach,” with a separate Norman place-name route.

Confidence: Likely
US frequency: Rank 519 · 63,424 people
Common variants: O'Casey, Ó Cathasaigh, MacCasey, Caisse

Confidence: Likely. The main story is well supported; some details of the deeper root are less certain.

The short story

Casey is chiefly an Irish patronymic surname, an anglicized form of Ó Cathasaigh, “descendant of Cathasach.” The personal name Cathasach is associated with watchfulness or vigilance, while several unrelated Irish septs used the surname. Casey can also have a Norman or English route from the place-name Pays de Caux, so not every bearer shares the Gaelic origin. O’Casey, Ó Cathasaigh, and MacCasey help with historical searches but are not interchangeable in every record. Parent’s name is the catalog lead, with likely confidence preserving the independent place-name alternative.

Also seen as: O'Casey, Ó Cathasaigh, MacCasey, Caisse

Sources used

Ancestry, Dictionary of American Family Names entry 'Casey' (Irish Ó Cathasaigh and Norman Pays de Caux routes)
Wikipedia 'Casey (surname)' (Irish septs and Norman alternative)
Names2020_LastNames_RaceHispanic_Top1000.xlsx (2020 Census)