O'Callaghan
O'Callaghan (/əˈkæləhən, oʊ-, -hæn, -ɡən, -ɡæn/), Ó Ceallacháin, or simply Callaghan without the prefix, is an Irish surname. Often when Irish migrated to the United States and the "g" was removed from the spelling in the ships' manifests.
The surname means descendent of Ceallachán who was the Eóganachta King of Munster from AD 935 until 954. The personal name means 'bright-headed'. The principal Munster sept of the name Callaghan were lords of Cineál Aodha in South Cork originally. This area is west of Mallow along the Blackwater river valley. The family were dispossessed of their ancestral home and 24,000 acres (97 km2) by the Cromwellian Plantation and settled in East Clare. In 1994, Don Juan O'Callaghan of Tortosa was recognised by the Genealogical Office as the senior descendant in the male line of the last inaugurated O'Callaghan.
The O'Callaghan land near Mallow, forfeited by Donough O'Callaghan after the Irish rebellion of 1641, came into the hands of a family called Longfield or Longueville, who built a 20-bedroom Georgian mansion there. In a twist of history, 500 acres (2.0 km2) of the ancient O'Callaghan land returned to O'Callaghan hands in the twentieth century, when Longueville House was bought by a descendant of Donough O'Callaghan. The ancestral estate of the O'Callaghans, now a luxury hotel, is owned by William O'Callaghan.
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