1865 in Ireland

Events

• 23 July – the sets out from Valentia Island on the first attempt to lay the transatlantic telegraph cable.
• Work begins on the building of the Albert Memorial Clock, Belfast, as a memorial to Queen Victoria's late Prince Consort, Prince Albert.

  Arts and literature

• 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.

  Births

• 6 February – Andrew Claude de la Cherois Crommelin, astronomer.
• 16 March – Patsy Donovan, Major League Baseball player and manager.
• 17 March – Patrick Joseph Sullivan, mayor of Casper, Wyoming and Republican member of the United States Senate from Wyoming.
• 20 April – James Macmahon, civil servant and businessman, Under-Secretary for Ireland from 1918 to 1922.
• 4 May – Charles A. Callis, member of the Quorum of the Twelve Apostles of The Church of Jesus Christ of Latter-day Saints.
• 7 May – John MacBride, nationalist rebel and Easter Rising leader.
• 8 May – Charles FitzClarence, soldier, recipient of the Victoria Cross for gallantry in 1899 near Mafeking, South Africa.
• 10 June – Dermod O'Brien, painter.
• 13 June – William Butler Yeats, poet and dramatist.
• 18 June – Henry Allan, painter.
• 24 June – Harry Plunket Greene, baritone.
• 15 July – Alfred Harmsworth, 1st Viscount Northcliffe, newspaper and publishing magnate
• 16 July – 'George A. Birmingham', novelist
• 29 August – Thomas Kent, nationalist rebel.
• 4 September – Alice Milligan, nationalist and poet.
• 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.
• 12 November – Herbert Trench, poet.
• ;Full date unknown
• :*Grace Rhys, née Little, novelist.
• :*Robert Henry Woods, Irish Unionist MP.

  Deaths

• 1 April – John Cuffe, 3rd Earl of Desart, Conservative politician..
• 23 May – Benjamin Holmes, businessman and politician in Quebec.
• 14 July – Nathaniel Burslem, soldier, recipient of the Victoria Cross for gallantry in.
• 25 July – Dr James Barry, military surgeon, revealed on death to be a woman, probably Margaret Ann Bulkley.
• 31 August – John Farrell, soldier and recipient of the Victoria Cross for gallantry at the 1854 Charge of the Light Brigade.
• 2 September – William Rowan Hamilton, mathematician, physicist, and astronomer.
• ;Full date unknown
• :*Jones Quain, anatomist.