of Trustees Families Need Father Roger Timothy O'Callaghan (1912-1654): US Jesuit and professor of biblical history, geography, and archaeology Seán O'Callaghan (1954–2017): IRA informer from Tralee, County Kerry Sian O'Callaghan (1988–2011): murder victim from Swindon, Wiltshire, UK Therése O'Callaghan: camogie player captain Places O'Callaghans Mills, County Clare, Ireland Callaghan, New South Wales, a suburb of Newcastle, New South Wales and home of the University of Newcastle, Australia Liscallaghan, old Irish name for Fivemiletown, County Tyrone Callaghan, Virginia, a census-designated place in the US Other Mount Callaghan Slim Callaghan, fictional private detective See also Irish nobility Eóganachta Eóganacht Chaisil Irish royal families Chief of the Name Callahan (disambiguation) Callaghan (disambiguation) Callihan Other Munster families McGillycuddy of the Reeks O'Donoghue O'Donovan O'Brien, Prince of Thomond O'Grady of Kilballyowen References Further reading Bugge, Alexander (ed. and tr.), Caithreim Cellachain Caisil: The Victorious Career of Cellachan of Cashel Christiania: J. Chr. Gundersens Bogtrykkeri. 1905. Curley, Walter J.P., Vanishing Kingdoms: The Irish Chiefs and their Families. Dublin: Lilliput Press. 2004. O'Hart, John, Irish Pedigrees. Dublin. 5th edition, 1892. External links Callahan Genealogy and History website Irish families Surnames of Irish origin Anglicised Irish-language surnames English-language surnames