O'Hara / Hara
O'Hara is a phonetic anglicisation of O hEaghra. The family clan descent from Eoghra, lord of Luighne (the modern Leyney) in Co Sligo, who died in 976 and who was himself, in the traditional genealogies, of the family of Oiloll Ollum, king of Munster. The O'Haras remain strongly associated with Co Sligo, where they were chiefs in two areas, O hEaghra Buidhe ('fair') around Collooney, and O hEaghra Riabhach ('grey') at Ballyharry, more properly 'Ballyhara'. In the fourteenth century a branch of the family migrated north to the Glens of Antrim and established themselves in the area around the modern town of Ballymena. There they intermarried with powerful local families and acquired great prominence themselves. Apart from Dublin, Sligo and Antrim are still the two regions where the surname is most concentrated."
The Irish name O'Hara is derived from the native Gaelic O'hEaghra Sept that was located in County Sligo. There were two chiefs named Buidhe and Riabhach. A branch migrated to County Sligo and it is in these two Counties that the majority of descendants can today be found.