O'Hannigan is an Irish surname, a variant of O'Hannagain. The surname originated from the Irish Ó hAnnagáin, meaning "descendant of Annagán". The personal name Annagán is a diminutive of Annadh, which translates to "delay" in Irish Gaelic. This etymological root gives the name a distinctively ancient Irish origin, rooted in the Gaelic naming tradition of forming denominal patronymics. Like many Irish surnames beginning with Ó (meaning "grandson" or "descendant"), O'Hannigan affiliates the bearer with a specific family lineage. Over time, the name took various anglicized forms, such as Hanegan, Hanigan, and Hannigan, each born of dropping the O' prefix or reflecting subtle divergences in pronunciation and spelling between regional dialects. The variant listing indicates a rich semiphonetic evolution from the original Irish form through centuries of scriptural and bureaucratic recording in English. Historically, families bearing these associated surnames can be traced through Irish civil parishes and diocesan registers. The adoption of particular forms—for instance, the preservation of the O’ in O'Hanigan versus its omission in Hanigan—may suggest different branches or times of migration. The surname distribution, as recorded by genealogy aggregators such as Forebears, shows concentrations in Irish counties with continuity of Gaelic-naming practices, as well as in descendant communities in the United States, Australia, and Britain. While O'Hannigan itself may be among the rarer anglicizations, its tie to the same familial fountainhead as more widespread forms underscores a shared ancestral narrative. The name stands as witness to the devolved writing conventions of Gaelic names during the post-medieval period and to the reshaping of an old patronymic in its encounter with the English administrative system. Meaning: Descendant of Annagán (a diminutive of Annadh, meaning "delay")Origin: Irish (Gaelic)Type: Patronymic surnameVariants: Hanegan, Hanigan, Hannigan, O'Hanegan, O'Hanigan, etc.