Denis O'Conor Don

Denis Armar O'Conor Don, (1912–10 July 2000) was hereditary chief of the O'Conor Don sept of Ireland.

Born in London in 1912 to Charles William O'Conor and Evelyn Lowry-Corry, he inherited his title in 1981 from his second cousin Fr. Charles O'Conor, a Jesuit priest. He used his position to promote an interest in Irish heritage from genealogy, local history to archaeology. He became President of the Dún Laoghaire Genealogical Society in 1991 and President of the Genealogical Society of Ireland in 1999.

He married Elizabeth Marris and they had a son, Desmond. With his second wife, Rosemay (née O'Connell Hewett), he had two sons: Kieran and Rory. A daughter, Gail, died aged thirteen.

His eldest son, Desmond, inherited his title of O'Conor Don.