1865 in Ireland

• 23 July – the {{SS|Great Eastern}} sets out from Valentia Island on the first attempt to lay the transatlantic telegraph cable.{{cite web|first=Bill|last=Glover|title=Great Eastern|url=http://www.atlantic-cable.com/Cableships/GreatEastern/|work=History of the Atlantic Cable & Undersea Communications|access-date=2013-03-21}}
• Methodist College Belfast founded by the church; it will open to pupils in 1868.
• Work begins on the building of the Albert Memorial Clock, Belfast, as a memorial to Queen Victoria's late Prince Consort, Prince Albert.

• 9 May – International Exhibition of Arts and Manufactures opens in Dublin.
• 23 December – Gustavus Vaughan Brooke concludes a farewell season in Belfast, playing the title role in Richard III.
• Augustus Burke paints Connemara Girl.
• Samuel Ferguson publishes his collected poems Lays of the Western Gael.

• 6 February – Andrew Claude de la Cherois Crommelin, astronomer (died 1939).
• 16 March – Patsy Donovan, Major League Baseball player and manager (died 1953 in the United States).{{cite book |last1=Eisenbath |first1=Mike |title=The Cardinals Encyclopedia |date=1999 |publisher=Temple University Press |location=Philadelphia |isbn=978-1-56639-703-2 |page=367 |url=https://books.google.com/books?id=hymGG28xYcoC&pg=PA367 |chapter=Donovan, Patsy}}
• 17 March – Patrick Joseph Sullivan, mayor of Casper, Wyoming and Republican member of the United States Senate from Wyoming (died 1935 in the United States).
• 20 April – James Macmahon, civil servant and businessman, Under-Secretary for Ireland from 1918 to 1922 (died 1954).
• 4 May – Charles A. Callis, member of the Quorum of the Twelve Apostles of the Church of Jesus Christ of Latter-day Saints (died 1947 in the United States).
• 7 May – John MacBride, nationalist rebel and Easter Rising leader (executed 1916).
• 8 May – Charles FitzClarence, soldier, recipient of the Victoria Cross for gallantry in 1899 near Mafeking, South Africa (killed in action 1914).
• 10 June – Dermod O'Brien, painter (died 1945).
• 13 June – W. B. Yeats, poet and dramatist (died 1939).
• 18 June – Henry Allan, painter (died 1912).
• 24 June – Harry Plunket Greene, baritone (died 1936).
• 15 July – Alfred Harmsworth, 1st Viscount Northcliffe, newspaper and publishing magnate (died 1922)
• 16 July – 'George A. Birmingham' (Rev. James Owen Hannay), novelist (died 1950)
• 29 August – Thomas Kent, nationalist rebel (executed following a gunfight with the RIC 1916).
• 4 September – Alice Milligan, nationalist and poet (died 1953).
• 16 October – Rudolph Lambart, 10th Earl of Cavan, British Army commander in World War I, later Chief of the Imperial General Staff and Field Marshal (died 1946).
• 12 November – Herbert Trench, poet (died 1923).
• ;Full date unknown
• :*Grace Rhys, née Little, novelist (died 1929).
• :*Robert Henry Woods, Irish Unionist MP (died 1938).

• 1 April – John Cuffe, 3rd Earl of Desart, Conservative politician. (born 1818).
• 23 May – Benjamin Holmes, businessman and politician in Quebec (born 1794).
• 14 July – Nathaniel Burslem, soldier, recipient of the Victoria Cross for gallantry in .

MOVE FROM *1865* TO 1789 *25 July – Dr James Barry, military surgeon, revealed on death to be a woman, probably Margaret Ann Bulkley (born 1789-1799).

• 31 August – John Farrell, soldier and recipient of the Victoria Cross for gallantry at the 1854 Charge of the Light Brigade (born 1826).
• 2 September – William Rowan Hamilton, mathematician, physicist, and astronomer (born 1805).
• ;Full date unknown
• :*Jones Quain, anatomist (born 1796).

• 1865 in Scotland
• 1865 in Wales

{{reflist}}

{{Years in Ireland}}

{{DEFAULTSORT:1865 in Ireland}}

Category:1860s in Ireland

Category:Years of the 19th century in Ireland

Ireland

Ireland