1866 in Wales

Centuries:	17th; 18th; 19th; 20th; 21st;
Decades:	1840s; 1850s; 1860s; 1870s; 1880s;
See also:	List of years in Wales; 1866 in The United Kingdom Ireland Scotland

This article is about the particular significance of the year 1866 to Wales and its people.

Incumbents

31 March — The last public execution in Wales takes place as Robert Coe is hanged in Swansea.
July — Launch of Yr Australydd, a Welsh language Calvinistic Methodist newspaper, in Victoria (Australia), edited by William Meirion Evans and Theophilus Williams.^[1]
5 September — The Pembroke and Tenby Railway is extended for passengers to Whitland.^[2]
6 September — Six people are killed in a railway derailment near Criccieth.
September — The song Hen Wlad Fy Nhadau — later to become the official national anthem of Wales — is sung for the first time at the National Eisteddfod held at Chester.
17 October — First confirmed death from a cholera epidemic in Carnarvon.^[3]
Sir George Gilbert Scott begins work on the renovation of Bangor Cathedral.
The Baptist Union of Wales is established.
Whiteford Lighthouse on Gower, the only wave-swept cast-iron lighthouse ever built in the UK, is first lit.^[4]
Edward Gordon Douglas is created Baron Penrhyn.

The National Eisteddfod of Wales is held at Chester in England.
- The harpist William Frost is awarded a pedal harp by Pencerdd Gwalia

Cricket — Hawarden Park Cricket Club is founded, reputedly by William Ewart Gladstone.

13 January — Frank Hill, Wales international rugby captain (died 1927)
21 January — Sir Owen Cox, politician and businessman in Australia (died 1932)
22 March — Willie Thomas, Wales international rugby captain (died 1921)
1 April — Sir William Henry Hoare Vincent, diplomat (died 1941)
18 April — Frederick Llewellyn-Jones, lawyer and politician (died 1941)
20 April — Sir John Milsom Rees, laryngologist (died 1952)
30 May — John Gruffydd Moelwyn Hughes, poet and hymn-writer (died 1944)
5 August — Sir Edward Anwyl, Celtic scholar (died 1914)
7 August — Charles Granville Bruce, mountaineer (died 1939)
13 August - William Finney, cricketer (died 1927)
24 August — Caesar Jenkyns, footballer (died 1941)
4 October — Robert Jones (Trebor Aled), poet (died 1917)
12 October — James Ramsay MacDonald, politician (died 1937)
4 November — Sir David William Evans, lawyer, public servant and Wales international rugby player, (died 1926)
5 November — Daniel Protheroe, conductor and choirmaster (died 1934)
14 November — Tom Morgan Wales international rugby player (died 1899)
24 November — Alexander Bland, Wales international rugby player (died 1947)
4 December — Dai Lewis (died 1943), rugby union forward who played international rugby for Wales
15 December — William Williams (rugby player), Wales national rugby union player (died 1945)
date unknown — David Delta Evans (Dewi Hiraddug), journalist, author, and Unitarian minister (died 1948)