Sir Cahir Rua O'Doherty ( or ; 1587–5 July 1608) was the last Gaelic Chief of the Name of Clan O'Doherty and Lord of Inishowen, in what is now County Donegal. O'Doherty was a noted loyalist during Tyrone's Rebellion and became known as the Queen's O'Doherty for his service on the Crown's side during the fighting. After the war O'Doherty had ambitions to become a courtier and applied for a position in the household of Henry Frederick, Prince of Wales, but he increasingly came into dispute with Irish-based officials such as the Viceroy Sir Arthur Chichester and the Governor of Derry Sir George Paulet. In 1608 he launched O'Doherty's Rebellion, seizing Derry from Paulet and burning it to the ground. O'Doherty was subsequently killed in a battle at Kilmacrennan, and the rebellion swiftly collapsed.