Recorded in several spellings including O'Hartigan, O'Hartagan, Hartegan, Hartigan, and Hartin, and being cognate with the surname O'Hart, this is a famous Irish surname. It originates from the pre 15th century Olde Gaelic surname O'hArtagain, which means the descendant of the son of Art, the latter being possibly a short form of Arthur. It is said that the tribe were Dalcassian, and originated from the region known as Thomond, which was made up of the modern counties of Clare, Limerick and Tipperary. According to the etymologies of Ireland by the late Professor Edward MacLysaght, the clan is best known in the late 20th century in County Limerick, but even there, it is no longer numerous. The best known of the original nameholders was a poet, Cineth O'Hartegan, who died over one thousand years ago in 975 a.d., whilst in the year 1643 Father Matthew O'Hartigan was a Catholic emissary to France on behalf of the Irish people. At this very dangerous time when religous strife was at its height throughout Europe, he also worked to assist various exiles who had been deported to the West Indies. Other interesting nameholders include James Hartigan, aged thirty four, who was an early emigrant from the infamous Potato Famine of 1846 - 1848. Recorded in the lists of arriving passengers for the Port of New York for the years 1846 - 1851, he left on the ship 'Elizabeth Denison of Liverpool' on July 20th 1846, whilst Thomas Hartin, left on the ship 'Garrick', also from Liverpool, on May 15th 1847.