The Gaois Linguistic Database of Irish-Language Surnames was designed to provide users with standard spellings of Irish-language surnames and their English-language equivalents.
It also provides users with inflected forms of the Irish-language surnames. Entries were selected for inclusion in the dataset based on frequency data from the Central Statistics Office in Ireland, i.e. the most frequent names registered for babies born in Ireland between 2016 and 2020. Surnames of Irish-language origin in Ireland are characterised by the fact that they are usually used in their anglicised form, but use of the Irish-language form is commonplace and on the increase in recent years, and this resource is designed to help users not literate in the language who wish to use the Irish-language form of their name.
For example, the top 3 most frequently registered surnames in 2020 were Murphy, Kelly, and O'Brien, which originate from the Irish-language surnames, Ó Murchú, Ó Ceallaigh, and Ó Briain. Other interesting examples include Mac/Ó Donncha(idh) (McDonagh, O'Donoghue, Donoghue, Dunphy, Donaghy) and Ó Maolchathaigh (Mulcahy).
See www.gaois.ie/en/surnames/info/ for more information.