22 March – thousands gather to pay their respects to the murdered Tomás Mac Curtain. Over 8,000 IRA Volunteers line the route to St. Finbarr's Cemetery. He is succeeded as Lord Mayor by Terence MacSwiney.
25 March – British recruits to the RIC begin to arrive in Ireland. They become known from their improvised uniforms as the "Black and Tans".[2]
13–14 April – Irish Trades Union Congress stages a general strike in support of the Mountjoy hunger strikers, securing their release.
15 April–8 June: Arthur Griffith establishes a Republican legal system (under Austin Stack) in areas under IRA control.[2] The traditional Summer Assizes become virtually unworkable.
20 May – Dublin dock workers refuse to handle British military material, and are soon joined in the boycott by members of the Irish Transport and General Workers Union.
4 June – the IRA orders a boycott of the RIC and their families.[2]
17 June – "The Listowel Mutiny": RIC constables based at Listowel refuse orders to assist the British Army.[2] The RIC is ordered to shoot armed IRA men who do not surrender when challenged.[2]
30 September – "Sack of Trim" in County Meath: "Black and Tans" destroy properties in the town following the previous day's raid on an RIC barracks by the IRA.[8]
1 November – an 18-year-old medical student, Kevin Barry, is executed in Mountjoy Prison for participating in the killing of three young unarmed British soldiers.[2]
11 December – The Burning of Cork: British forces set fire to some 5 acres (20,000 m2) of the centre of Cork (city), including the City Hall, in reprisal attacks after a British auxiliary is killed in a guerilla ambush.
Winners: Shelbourne (final not played). Disorder at the other semi-final which is abandoned means both potential opponents are excluded from the competition and the Irish Football Association award the cup to Shelbourne.
Gaelic Gamesedit
The All-Ireland Champions are Dublin (hurling) and Tipperary (football)
^Fox, Seamus (31 August 2008). "January 1920". Chronology of Irish History 1919–1923. Dublin. Archived from the original on 5 March 2012. Retrieved 31 October 2012.
^ abcdefghijklmnCottrell, Peter (2009). The War for Ireland, 1913–1923. Oxford: Osprey Publishing. ISBN 978-1-84603-9966.
^Fox, Seamus (31 August 2008). "April 1920". Chronology of Irish History 1919–1923. Dublin. Archived from the original on 26 June 2012. Retrieved 31 October 2012.
^"Decree debate and text, 29 June 1920". Office of the Houses of the Oireachtas. 29 June 1920. Archived from the original on 7 June 2011. Retrieved 31 October 2012.
^"21st July 1920: Expulsions from Harland & Wolff". Decade of Centenaries: Ulster 1885-1925. Retrieved 29 November 2018.
^Fox, Seamus (31 August 2008). "September 1920". Chronology of Irish History 1919–1923. DCU. Archived from the original on 22 August 2009. Retrieved 23 August 2012.
^French, Noel (2020). "The burning of Trim Barracks and reprisals". Ríocht na Midhe. 31: 184–210.
^Parkinson, Alan F. (2004). Belfast's Unholy War. Dublin: Four Courts Press. p. 84. ISBN 1-85182-792-7.
^Hezlet, Arthur (1972). The B-Specials: A History of the Ulster Special Constabulary. p. 19. ISBN 0-85468-272-4.
^O'Halpin, Eunan (2020). The Dead of the Irish Revolution, Yale University Press, pg. 234, ISBN 978-0-300-12382-1.
^"Mr. Arthur Griffith (Arrest)". Parliamentary Debates (Hansard). 26 November 1920. Archived from the original on 7 August 2016. Retrieved 28 May 2017.
^Williams, Hywel (2005). Cassell's Chronology of World History. London: Weidenfeld & Nicolson. pp. 488–490. ISBN 0-304-35730-8.
^Mac Liammoir, Michael; Boland, Eavan (1971). "Chronology". W. B. Yeats. Thames and Hudson Literary Lives. London: Thames and Hudson. p. 132.