Sir Hugh O'Donnell

Hugh McManus O'Donnell (Irish: Sir Aodh mac Maghnusa Ó Domhnaill; c. 1520 – 7 December 1600) was a Gaelic Irish nobleman, best known as the father of Hugh Roe O'Donnell. He was clan chief of the O'Donnell clan and Lord of Tyrconnell during the Elizabethan era.

In 1561, O'Donnell imprisoned his half-brother and rival Calvagh with the assistance of Shane O'Neill. Under brehon law he succeeded as The O'Donnell upon Calvagh's death in 1566. A "wary politician", O'Donnell's lordship was marked by political indecision. He attempted to appease both pro- and anti-English factions in Tyrconnell, and thus alternated between varying alliances. His clan ultimately united with long-time enemies the O'Neills against the English – this alliance would continue into the Nine Years' War (1593–1603).

O'Donnell's health had heavily declined by the 1580s, leading to a major succession crisis which was compounded by the kidnapping of his son and tanist Hugh Roe O'Donnell. His second wife, Scottish noblewoman Iníon Dubh, organised his abdication in 1592, in favour of Red Hugh.