The Royal Irish Constabulary (RIC), the police force in Ireland from 1822 until 1922, when all of the island was part of the United Kingdom, is disbanded on August 17, 1922, and replaced by the Garda Síochána.

A separate civic police force, the unarmed Dublin Metropolitan Police (DMP), patrols the capital and parts of County Wicklow, while the cities of Derry and Belfast, originally with their own police forces, later have special divisions within the RIC. For most of its history, the ethnic and religious makeup of the RIC broadly matches that of the Irish population, although Anglo-Irish Protestants are overrepresented among its senior officers.

The first organised police forces in Ireland come about through Dublin Police Act 1786, which is a slightly modified version of the failed London and Westminster Police Bill 1785 drafted by John Reeves at the request of Home Secretary Thomas Townshend, 1st Viscount Sydney, following the Gordon Riots of 1780. The force is viewed as oppressive by local elites and becomes a strain on the city budget. The arguably excessive budget is used as a pretext by Irish nationalist MP Henry Grattan and short-lived Lord Lieutenant of Ireland William Fitzwilliam, 4th Earl Fitzwilliam, to essentially abolish the Dublin Police in 1795 and even temporarily move it under Dublin Corporation.

The Peace Preservation Act 1814, for which Sir Robert Peel is largely responsible, and the Irish Constabulary Act 1822 forms the provincial constabularies. The 1822 act establishes a force in each province with chief constables and inspectors general under the United Kingdom civil administration for Ireland controlled by the Dublin Castle administration.

The RIC’s existence is increasingly troubled by the rise of the Home Rule campaign in the early twentieth century period prior to World War I.

In January 1922, the British and Irish delegations agree to disband the RIC. Phased disbandments begin within a few weeks with RIC personnel both regular and auxiliary being withdrawn to six centres in southern Ireland. On April 2, 1922, the force formally ceases to exist, although the actual process is not completed until August 17. The RIC is replaced by the Civic Guard (renamed as the Garda Síochána the following year) in the Irish Free State and by the Royal Ulster Constabulary (RUC) in Northern Ireland.

According to a parliamentary answer in October 1922, 1,330 ex-RIC men join the new RUC in Northern Ireland. This results in an RUC force that is 21% Roman Catholic at its inception in 1922. As the former RIC members retire over the subsequent years, this proportion steadily falls.

Just thirteen men transfer to the Garda Síochána. These include men who had earlier assisted Irish Republican Army (IRA) operations in various ways. Some retire, and the Irish Free State pays their pensions as provided for in the terms of the Anglo-Irish Treaty agreement. Others, still faced with threats of violent reprisals, emigrate with their families to Great Britain or other parts of the British Empire, most often to join police forces in Canada, Australia, New Zealand, South Africa and Southern Rhodesia. A number of these men join the Palestine Police Force, which is recruiting in the UK at the time.