Lord Lieutenant of Ireland (), or more formally Lieutenant General and General Governor of Ireland, was the title of the chief governor of Ireland from the Williamite Wars of 1690 until the Partition of Ireland in 1922. This spanned the Kingdom of Ireland (1541–1800) and the United Kingdom of Great Britain and Ireland (1801–1922). The office, under its various names, was often more generally known as the viceroy, and his wife was known as the vicereine.
Importance of the post
The post ebbed and flowed in importance, being used on occasion as a form of exile for prominent British politicians who had fallen afoul of the Court of St. James's or Westminster. On other occasions it was a stepping stone to a future career. Two Lords Lieutenant, Lord Hartington and the Duke of Portland, went from Dublin Castle to 10 Downing Street as Prime Minister of Great Britain, in 1756 and 1783 respectively.
By the mid-to-late 19th century the post had declined from being a powerful political office to that of being a symbolic quasi-monarchical figure who reigned, not ruled, over the Irish administration. Instead it was the Chief Secretary for Ireland who became central, with him, not the Lord Lieutenant, sitting on occasion in the British cabinet.
Official residence
thumb|190px|right|The Viceregal Apartments in Dublin Castle – the official 'season' residence of the Lord Lieutenant
The official residence of the Lord Lieutenant was the Viceregal Apartments in Dublin Castle, where the Viceregal Court was based. Other summer or alternative residences used by Lord Lieutenant or Lords Deputy included Abbeville in Kinsealy, Chapelizod House, in which the Lord Lieutenant lived while Dublin Castle was being rebuilt following a fire but which he left due to the building being supposedly haunted, Leixlip Castle and St. Wolstan's in Celbridge. The office survived until the establishment of the Irish Free State in 1922.
Irish nationalists throughout the 19th century and early 20th century campaigned for a form of Irish self-government. Daniel O'Connell sought repeal of the Act of Union, while later nationalists such as Charles Stewart Parnell sought a lesser measure, known as home rule. All four Home Rule bills provided for the continuation of the office, typically with a ceremonial role as the monarch's representative in Ireland, similar to the Governor General of Canada or Australia.
Abolition
The Government of Ireland Act 1920 divided Ireland into two devolved entities inside the United Kingdom, Northern Ireland and Southern Ireland. Two institutions were meant to join the two; a Council of Ireland (which was hoped would evolve into a working all-Ireland parliament) and the Lord Lieutenant who would be the nominal chief executive of both regimes, appointing both prime ministers and dissolving both parliaments. In fact only Northern Ireland functioned, with Southern Ireland being quickly replaced by the Irish Free State with its own Governor-General. The Irish Free State (Consequential Provisions) Act 1922 provided that, once the Parliament of Northern Ireland opted out of the Free State, the office of Lord Lieutenant of Ireland would be abolished and its remaining powers transferred to the new position of Governor of Northern Ireland. This duly happened on 8 December 1922, two days after the Free State Constitution came into force.