1805 in Ireland

Events

• August – rebel leader Michael Dwyer, held without sentence in Kilmainham Gaol, is transported to Sydney, where he lands as a free settler in February 1806.
• 21 October – Battle of Trafalgar: a British Royal Navy fleet led by Admiral Horatio Nelson defeats a combined French and Spanish fleet off the coast of Spain. Almost 4,000 of the 18,000 men on the British ships were born in Ireland.

Publications

• Mary Tighe's poem ''Psyche, or the Legend of Love''

Births

• 2 January – John Hogan, businessman and United States Representative from Missouri.
• 5 April – Samuel Forde, painter from Cork.
• 4 August – William Rowan Hamilton, mathematician, physicist, and astronomer.
• 2 December - William Thompson, naturalist.
• ;Full date unknown
• :*Jon Riley, deserter from United States Army, a founder of the San Patricios.
• :*Anthony Coningham Sterling, British Army officer and historian.

Deaths

• 27 April – William Trench, 1st Earl of Clancarty, politician and statesman.
• 7 May – William Petty, 2nd Earl of Shelburne, British Whig statesman, Home Secretary in 1782 and Prime Minister 1782–1783.
• 18 June – Arthur Murphy, editor and writer.
• 27 July – Brian Merriman, Irish language poet and teacher.
• August – John Talbot Dillon, traveller and historical writer.
• 8 December – Rose ffrench, 1st Baroness ffrench.