The Irish War of Independence (or the Anglo-Irish War) of 1919–1921 was a guerrilla conflict, and most of the fighting was conducted on a small scale by the standards of conventional warfare.

Although there were some large-scale encounters between the Irish Republican Army (IRA) and the state forces of the United Kingdom (Royal Irish Constabulary (RIC)/Auxiliary Division and Dublin Metropolitan Police (DMP) paramilitary units—the Black and Tans, the Ulster Special Constabulary (USC) and the regular British Army), most of the casualties were inflicted in assassinations and reprisals on either side. The war began with an unauthorised ambush by IRA volunteers Dan Breen and Seán Treacy at Soloheadbeg in 1919 and officially ended with a truce agreed in July 1921. However, violence continued, particularly in the disputed territory of Northern Ireland, until mid-1922 (see The Troubles in Ulster (1920–1922)). In the rest of Ireland, the war was followed by the Irish Civil War between supporters and opponents of the Anglo-Irish Treaty.

1919

January 1919 21 January: Sinn Féin TDs assembled in Dublin, forming the First Dáil and issuing the Irish Declaration of Independence. Soloheadbeg ambush: IRA volunteers of the 3rd Tipperary Brigade, acting on their own initiative, ambushed and killed RIC officers Patrick O'Connell and James McDonnell at Soloheadbeg, County Tipperary. The volunteers, who had planned to seize the gelignite explosives the officers were escorting, said that the officers aimed their rifles when asked to surrender. The two officers were accompanied by two council workers who were unharmed. 31 January: following a meeting of the Executive of the Irish Volunteers, the editorial of An t-Óglach (the official publication of the Irish Volunteers) stated that the formation of Dáil Éireann "justifies Irish Volunteers in treating the armed forces of the enemy – whether soldiers or policemen – exactly as a National Army would treat the members of an invading army".

February 1919 3 February 1919: Éamon de Valera (president of Sinn Féin) escaped from Lincoln Gaol, along with Seán McGarry and Seán Milroy. The escape was masterminded by Harry Boland and Michael Collins. All were members of Sinn Féin. 23 February 1919: at a Brigade meeting in Nodstown Tipperary, officers of the Third Tipperary Brigade drafted a proclamation (signed by Seumus Robinson as O/C) ordering all British military and police forces out of South Tipperary and, if they stayed they would be held to have "forfeited their lives". The leadership of the Irish Volunteers in Dublin refused to sanction the proclamation and demanded it not be publicly displayed. Despite this it was still posted in several places in Tipperary.Sean Treacy and the 3rd. Tipperary Brigade by Desmond Ryan (Tralee 1945)Bureau of Military History, Witness Statement 1721, Séumas RobinsonHansard - HC Deb 8 May 1919 vol 115 cc1077-80

March 1919 19 March 1919: IRA volunteers raided Collinstown Airfield, now Dublin Airport. They captured 75 rifles and 4,000 rounds of ammunition. (Henderson says the raid occurred on 20 March and that 6,000 rounds of ammunition were captured.) 29 March 1919: Resident Magistrate John Charles Milling was assassinated in Westport, County Mayo for sending IRA volunteers to prison for unlawful assembly and drilling.

April 1919 1 April 1919: Second meeting of Dáil Éireann – Éamon de Valera was elected President of Dáil Éireann (or Príomh Aire) and appointed the government of the 1st Dáil. De Valera issued a statement that "There is in Ireland at this moment only one lawful authority, and that authority is the elected Government of the Irish Republic". 6 April 1919: Limerick City IRA volunteers attempted to free a prisoner from Limerick Prison. RIC officer Martin O'Brien (aged 35) was killed, and another wounded. The prisoner, Robert Byrne, was also wounded and died later that day. An RIC patrol was ambushed at Eyeries, County Cork. Three officers were shot and wounded. 10 April 1919: Third meeting of Dáil Éireann – the Dáil passed a motion calling on Irish people to ostracise the RIC. De Valera stated, "The Minister of National Defense is, of course, in close association with the voluntary military forces which are the foundation of the National Army". The British authorities declared counties Limerick, Tipperary, Cork, Kerry and Roscommon to be in a state of disturbance. 15–27 April 1919: The Limerick Soviet – the British declared Limerick to be a "Special Military Area" under the Defence of the Realm Act. Special permits were to be issued by the RIC and would have been required to enter the city. In protest, the Limerick Trades & Labour Council called a general strike and boycott of British troops. A strike committee was set up to print money, control food prices and publish newspapers.

May 1919

13 May 1919: Rescue at Knocklong, County Limerick – captured IRA volunteer Seán Hogan was rescued from a train by his comrades while being guarded by four armed RIC officers. Two of the RIC officers were killed—Sergeant Peter Wallace (aged 47) and Constable Michael Enright (aged 35)—and several IRA volunteers were wounded. 17 May 1919: First of the Dáil Courts was set up at Ballinrobe, County Mayo. Dáil Éireann sent a letter to the head of the Paris Peace Conference, repudiating Britain's claim to speak for Ireland. Soon after, it sent a statement concerning "Ireland's Case for Independence" to the Conference.

June 1919 1 June 1919: De Valera departed for the United States. He sought to gain official recognition of the Irish Republic from the US government, to secure the support of the American people and to raise money for Dáil Éireann and the IRA. 6 June 1919: The United States Senate passed a resolution asking for the delegation appointed by Dáil Éireann to be given a hearing at the Paris Peace Conference and expressing sympathy with the "aspirations of the Irish people for a government of their own choice". 16 June 1919: IRA volunteers ambushed a six-man British Army-RIC patrol at Rathclarin, County Cork and seized their rifles. A soldier and a volunteer were injured. 18 June 1919: The Dáil officially established the Dáil Courts. The next day it approved the First Dáil Loan. 23 June 1919: IRA volunteers assassinated RIC District Inspector Michael Hunt in Thurles, County Tipperary. 24 June 1919: Two RIC officers were attacked and disarmed near Meenascarthy, County Kerry. Ten IRA volunteers were later arrested and five of them sentenced to prison terms.Kerry's Fighting Story 1916-1921. Originally published by The Keeryman, 1947. Mercier Press, Cork; . pp. 204/205.

July 1919 4 July 1919: Sinn Féin, the Irish Volunteers, Cumann na mBan and the Gaelic League were declared illegal in County Tipperary. 12 July 1919: Ulster Unionist Party leader Edward Carson warned that if any moves were made to separate Ulster from the United Kingdom he would call out the Ulster Volunteers. 30 July 1919: RIC Detective Sergeant Smith was shot and fatally wounded outside his home in Drumcondra, Dublin. It was the first assassination authorised by Michael Collins and carried out by The Squad.Mackay, James. Michael Collins: A Life, p. 132.

August 1919 4 August 1919: Two RIC officers were fatally shot by the IRA while on patrol near Ennistymon, County Clare. An IRA volunteer was wounded in the action. 20 August 1919: Motion passed by Dáil that an Oath of Allegiance (to the Republic) should be taken by all members and officials of Dáil Éireann and all Irish Volunteers. Volunteers began taking the oath on 25 August. O'Malley (new ed. 1990) says that with this oath the Irish Volunteers became the Irish Republican Army (IRA). 23 August 1919: Francis Murphy (15), a member of Fianna Éireann, was shot dead by British soldiers who fired into his home near Ennistymon, County Clare. It was allegedly retaliation for the recent IRA ambush nearby. Although the British Army denied responsibility, an inquest found them responsible.Marrinan, Rita (1982). The War of Independence in West Clare. "The Beginning of the War in West Clare". Clare County Library.

September 1919 2 September 1919: An RIC Sergeant was killed and another wounded when their bicycle patrol was ambushed by IRA volunteers from the 1st Tipperary Brigade in Lorrha. Authorisation for the attack was given by Treacy and Breen, who were on the run in the area after the Soloheadbeg ambush and Knocklong attack earlier in the year. 7 September 1919: Fermoy ambush: The IRA ambushed British soldiers on their way to a church service outside the Methodist church in Fermoy, County Cork, where the service was being held. The IRA aim was to seize weapons. It was the first such action against the British Army. The ambush involved twenty-three Cork IRA volunteers, under the leadership of Liam Lynch, augmented by Mick Mansfield and George Lennon of Waterford. One soldier, Private William Jones, 2nd Battalion King's Shropshire Light Infantry, was killed. Lynch himself was wounded but survived. Fifteen rifles were captured by the IRA. Following the ambush, approximately 200 British soldiers attacked and looted businesses in the town. 10 September 1919: The Dáil was outlawed by the British government. 12 September 1919: Detective Constable Daniel Hoey of G Division (Dublin Metropolitan Police) was assassinated by the IRA in Dublin. 19 September 1919: Official founding of "the Squad", an IRA counter-intelligence and assassination squad.

October 1919 19 October 1919: Constable Michael Downing of G Division (Dublin Metropolitan Police) was assassinated by the IRA in Dublin. 31 October 1919: The IRA attacked Ballivor RIC barracks in County Meath, killing an RIC officer and seizing weaponry.

November 1919 4 November 1919: The British government's Irish Committee settled on a policy of creating two Home Rule parliaments—one in Dublin and one in Belfast—with a Council of Ireland to provide a framework for possible unity. 11 November 1919: First edition of the Irish Bulletin was produced by Dáil Éireann's Department of Publicity. It was to be produced every few days from this date onward and became very important in getting the Irish side of events known to a wide audience. 17 November 1919: Men of the 3rd Cork Brigade raided a British sloop whilst it was docked at a pier in Bantry, County Cork. The IRA men succeeded in capturing a number of arms and ammunition from the ship, greatly increasing the brigade's military capabilities in West Cork. 29 November 1919: Detective John Barton of G Division (Dublin Metropolitan Police) was assassinated by the IRA in Dublin.

December 1919

12 December 1919: In response to the arrest of three volunteers, the IRA shot and wounded a group of four RIC officers outside Dungloe, County Donegal.Ó Duibhir, Liam. The Donegal Awakening: Donegal & the War of Independence. Mercier Press, 2009. pp. 113-116 It was the first IRA action in the county during the conflict."Donegal's first shots of the War for Independence". Derry Journal, 10 December 2009. 14 December 1919: An RIC officer was killed by the IRA in Kilbrittain, County Cork. 19 December 1919: The IRA attempted to assassinate the Lord Lieutenant of Ireland, British Field Marshal Viscount French, in his car at Phoenix Park, Dublin. French was unhurt, but one IRA volunteer, Martin Savage, was killed. Dan Breen and two Dublin Metropolitan Policemen and a driver were wounded. An RIC Sergeant was knocked unconscious. 22 December 1919: The Government of Ireland Act 1920 also known as the Better Government of Ireland Bill was introduced into the House of Commons. It proposed two parliaments; one for the six counties of north-east Ulster and one for the other twenty-six counties of Ireland.

1920

January 1920