1855 in Ireland

Events

• 5 April – opening of Boyne Viaduct at Drogheda by the Dublin and Belfast Junction Railway completes permanent through rail communication between the two principal cities of Ireland.
• October – Charles Gavan Duffy, founder of the Tenant Right League, emigrates to Australia.
• Charlemont Bridge over the River Blackwater, between Moy and Charlemont is constructed.
• The Roman Catholic St Mary's Cathedral, Killarney, is completed.
• Dublin Zoo buys its first pair of lions.

  Arts and literature

• The Society for the Preservation and Publication of the Melodies of Ireland publishes The Ancient Music of Ireland edited by George Petrie, including the first publication of the Londonderry Air as collected from a local fiddle player by Miss Jane Ross of Limavady.

  Births

• 17 May – Timothy Michael Healy, Nationalist politician, journalist, author, barrister and first Governor-General of the Irish Free State.
• 17 August – Andrew Jameson, public servant, businessman and Seanad member.
• 25 August – Paddy Glynn, Attorney General of Australia and Minister for External Affairs.
• 11 September – William Mulholland, water service engineer in Southern California.
• ;Full date unknown
• :*Margaret Wolfe Hungerford, novelist.
• :*James Nowlan, President of the Gaelic Athletic Association .

  Deaths

• 14 March – Edward Ffrench Bromhead, mathematician
• 13 August – Richard Bourke, soldier and Governor of New South Wales, Australia from 1831 to 1837.
• James Hardiman, lawyer, librarian and historian.