Delahunty. A true Gaelic-Irish surname, which has also been anglicized Delahunt and Dulanty, is Ó Dulchaointigh in Irish. O'Dolleghenty, O'Dulleghyntie are old forms in English as well as other similar variants, under which people of the name appear often in the Ormond Deeds from 1441 onwards, as well as in the Tudor Fiants and other mediaeval and early modern Irish records. In the "census" of 1659 the spellings are Dultaliunty and Dullchanty, the first was one of the principal names in the barony of Crannagil, Co. Kilkenny, and the second in the barony of Ballybritt, Co. Offaly. In the 1670s there were 27 families of the name included in the Hearth Money Rolls of County Tipperary, and twenty years later three officers of the name are found in a regiment of James 11's Irish army. The sept was always closely associated with that part of the country and was of the same stock as the famous O'Carrolls of Ely O'Carroll. A branch migrated to Co. Kerry in the sixteenth century but is seldom found there today, the Ely O'Carroll country is still their principal habitat. Best known of them in Ireland is probably John Whelan Dulanty, (d. 1955) who was 18 years Irish High Commissioner (later ambassador) in London. In America, as Delahunty, it recalls great feats in the game of baseball. Delahunty has taken the form Dulhunty in Australia.  Source:  Edward MacLysaght, More Irish Families, Dublin, 1996, pages 78-79.