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Decades: 1840s • 1850s • 1860s • 1870s • 1880s Centuries: 17th • 18th • 19th • 20th • 21st See also: 1866 in the United Kingdom Other events of 1866 List of years in Ireland

Events

• 14 October - St Peter's Cathedral, Belfast is dedicated, although the building is incomplete.

Births

• 5 February - Domhnall Ua Buachalla, member of 1st Dáil, Fianna Fáil TD, last Governor-General of the Irish Free State (d.1963).
• February - Michael Egan, trade unionist, city councillor, and Cumann na nGaedheal TD (d.1947).
• 15 June - Charles Wood, composer (d.1926).
• 3 December - Ethna Carbery, writer and poet (d.1902).
• December - Thomas Byrne, recipient of the Victoria Cross for gallantry in 1898 at the Battle of Omdurman, Sudan (d.1944).

Full date unknown

• Éamon a Búrc, tailor and seanchaí (d.1942).
• Dora Sigerson Shorter, poet (d.1918).
• Bridget Sullivan, domestic housemaid for Borden family of Fall River, Massachusetts (d.1948).

Deaths

• 5 January - Augustus Warren Baldwin, naval officer and political figure in Upper Canada (b.1776).
• 4 March - Alexander Campbell, religious leader in Britain and the United States (b.1788).
• 26 October - John Kinder Labatt, brewer in Canada (b.1803).
• 26 October - Patrick McHale, soldier, recipient of the Victoria Cross for gallantry in 1857 at Lucknow, India (b.1826).

Full date unknown

• Edward Eagar, lawyer and criminal transported to Australia, politician (b.1787).
• Francis Sylvester Mahony, humorist and poet (aka Father Prout), (b.1804).