1691 in Ireland

Incumbent

12 July – Williamite War in Ireland: Battle of Aughrim in County Galway:{{cite book |title=The Oxford companion to Irish history |publisher=Oxford University Press |isbn=9780199691869 |page=33 |edition=2nd}} Protestant Williamite forces led by Godert de Ginkell decisively defeat Jacobites under the Marquis de St Ruth (who is killed).
22 July – surrender and treaty of Galway.
August–October – Williamite War in Ireland: Siege of Limerick.
3 October – Treaty of Limerick ends the Williamite War. Its terms are immediately broken by the English.
22 December – the Flight of the Wild Geese begins, as Patrick Sarsfield, 1st Earl of Lucan leads 19,000 Irish soldiers on ships to France, Spain and onwards to join the armies of Europe.
Sir William Petty's Political Anatomy of Ireland (written 1672) is first published, posthumously in Dublin.

August – Claud Hamilton, 4th Earl of Abercorn, Jacobite and soldier, fought at the Battle of the Boyne (b. 1659)Cokayne, George E.: "The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom; Extant, Extinct, or Dormant", page 153.
18 September – Giles Alington, 4th Baron Alington (b. 1680)
30 December – Robert Boyle, natural philosopher (b. 1627)