Tyrconnell or Tirconnell (Irish: Tír Chonaill, meaning "Land of Conall") was a political state in northwest Ireland until 1601. It lay in the area now more commonly referred to as County Donegal, although the kingdom and later principality of Tyrconnell was larger than that, including parts of Sligo, Leitrim (in present-day Republic of Ireland), Tyrone, Fermanagh and a southern part of Londonderry (in present-day Northern Ireland). According to Geoffrey Keating, it included the baronies of Carbury (Cairbre, in County Sligo), Rosclogher (Dartrighe, in County Leitrim), and Magheraboy (Machaire Bui, mainly Toorah or Tuath Ratha) and Firlurg (Lorg, in County Fermanagh). As such it had a size varying between that of Corsica (8,680 km2) and Lebanon (10,452 km2).
It was founded in the fifth century by a son of Niall of the Nine Hostages, Conall Gulban, of whom the Cenél Conaill were descended. His descendants of the O'Donnell dynasty ruled the kingdom till the Flight of the Earls in September 1607, which marked the end of the kingdom.
Although the Chieftaincy of O'Donnell is extinct, the Chief of the Name is known as The O'Donnell of Tyrconnell, as recognised by the Chief Herald of Ireland, as the legitimate successor in a putative sequence of Chiefs of the Name, and will default to the Duke of Tetuan in Spain in succession to the current Chief, a Franciscan priest, who has no eligible progeny. The Hereditary Seneschal of Tyrconnell (currently vested in a living O'Donnell, who was already ennobled as a Knight of Malta, and who inherited the Seneschalship from his father), survives under the auspices of the Hereditary Great Seneschal or Lord High Steward of Ireland, currently Charles Chetwynd-Talbot, 22nd Earl of Shrewsbury, senior direct descendant of George Carpenter, 2nd Earl of Tyrconnell (of the 4th creation), and senior kin of Richard Talbot, Duke of Tyrconnel.