1820 in Wales

Incumbents

• Prince of Wales – George
• Princess of Wales – Caroline of Brunswick

  Events

• 29 January – The Prince of Wales becomes King George IV on the death of King George III of the United Kingdom.
• 14 April - At the completion of the United Kingdom general election:
• *Henry Paget, later Marquess of Anglesey, is elected as member for Anglesey.
• *Wyndham Lewis is elected for Cardiff.
• *Christopher Cole is re-elected for Glamorganshire.
• 24 June – The Honourable Society of Cymmrodorion is revived, having been in abeyance since 1787.
• date unknown
• *The first "colliery school" in the South Wales coalfield is established at Hirwaun.
• *Thomas Price founds a Welsh school at Gelli Felen.
• *Crawshay Bailey becomes a partner at Nant-y-glo ironworks with his brother, Joseph Bailey.
• *John Scandrett Harford meets Bishop Thomas Burgess and offers to donate the site of Lampeter Castle for the construction of St David's College.
• *Tondu Ironworks is built by Sir Robert Price.

  Arts and literature

New books

• Felicia Hemans – The Sceptic
• John Jones – Traethawd ar Gadwedigaeth yr Iaith Gymraeg
• Robert Jones – Drych yr Amseroedd
• William Probert - Y Gododdin

  Music

• Edward Jones – Hen Ganiadau Cymru

  Births

• 13 May - Robert Owen, theologian
• 21 May – Sir Thomas Lloyd, 1st Baronet, politician and landowner
• 22 May - Sir Watkin Williams-Wynn, 6th Baronet, politician
• 20 June – Thomas Essile Davies, poet
• 5 September – Evan Jones, minister and journalist

  Deaths

• 20 January - Eliezer Williams, clergyman and genealogist, 75
• 29 January – King George III of the United Kingdom, Prince of Wales 1751–1760, 81
• 6 May – Wilmot Vaughan, 2nd Earl of Lisburne, landowner, 64
• 16 June – Thomas Jones of Denbigh, Methodist preacher and writer, 64
• 27 June – William Lort Mansel, bishop and academic, 67
• 23 August – Edward Randles, harpist, 57
• 28 August – Henry Mills, musician, 63