Timeline of the Irish Civil War This is a timeline of the Irish Civil War , which took place between June 1922 and May 1923 . It followed the Irish War of Independence ( 1919 – 1921 ) , and accompanied the establishment of the Irish Free State as an entity independent from the United Kingdom . The conflict was waged between two opposing groups of Irish nationalists : the forces of the new Irish Free State , who supported the Anglo - Irish Treaty under which the state was established , and the Republican opposition , for whom the Treaty represented a betrayal of the Irish Republic . The Government of the Irish Free State ( established as a Provisional Government in January 1922 and as a full government in December 1922 ) was ultimately victorious . The anti - Treaty forces called a ceasefire in April 1923 and ordered their men to " dump arms " in May 1923 . The war involved both conventional warfare ( late June – August 1922 ) when the Free State forces took the major towns and cities , and then a longer period of guerrilla warfare ( September 1922 – April 1923 ) as the anti - Treaty forces were gradually brought to a standstill . " See also IRA and the Anglo - Irish Treaty " 16 August – 300 men of the Anti - Treaty IRA 4th Northern Division under Frank Aiken attack Dundalk . They use two mines to breach the walls of the barracks and temporarily take over the town . Five Free State private soldiers and one Commandant , Byrne in the attack on the barracks and another soldier is killed in the town centre . There are fifteen wounded Free State troops . Two Republicans are killed , accidentally by one of their own mines and thirty wounded . About 240 Republican prisoners are freed from the prison and 400 rifles are taken . However , Aiken does not try to hold the town and , while in possession of it , calls for a truce in a meeting in the town square . Appendix . Statistics are incomplete , Free State government sources stated that between 540 and 800 National Army soldiers were killed in the war . Historian Michael Hopkinson , in Green against Green , p272 - 3 , states " There are no means by which to arrive at even approximate figures for the dead and wounded . Mulcahy stated that around 540 pro - Treaty troops were killed between the Treaty ' s signing and the war ' s end ; the government referred to 800 army deaths between January 1922 and April 1924 . There was no record of overall Republican deaths , which appear to have been very much higher . No figure exists for total civilian deaths . " Deaths by date . Total for 1922 and 1923 : 857 - 961 . With additional statistics – fatalities by county available for : Cork 180 , Kerry 185 , Sligo 54 , Offaly 21 . Anti Treaty combatants killed in Clare : 28 ( no reliable statistics for pro Treaty / Civilians ) . Pro / Anti Treaty combatants killed between January – June 1922 , 9 , - 2 in Clare . Casualties in County Kildare , 45 killed . ( 17 National Army ) Additions , : Kerry + 78 , Cork + 120 , Sligo + 39 , Offaly + 19 , Clare + 27 , January – June clashes + 7 = 290 Revised total : 1 , 147 - 1 , 251 * A range is given where casualties are reported but not confirmed . < nowiki > * < / nowiki > this is not a definitive total , but rather what could be found in this article . Status of those killed . < nowiki > * < / nowiki > Civilian casualties , may be far higher , casualties for the Dublin fighting are given as 250 , but it is not clear how many of these were killed and how many wounded .