1840 in Wales

This article is about the particular significance of the year 1840 to Wales and its people.

Incumbents

1 January - Trial of Chartists John Frost, Zephaniah Williams and William Jones for their part in the Newport Rising of 1839 continues at Monmouth before Chief Justice Tindal. This is the first trial where proceedings are recorded in shorthand.
16 January - Frost, Williams and Jones are all found guilty of high treason for their part in the Chartist riots, and are sentenced to death - the last time the sentence of hanging, drawing and quartering is passed in the United Kingdom, although following a nationwide petitioning campaign and, extraordinarily, direct lobbying of the Home Secretary by the Lord Chief Justice, it is commuted to transportation for life.
5 June - Joseph Brown is appointed Vicar Apostolic of the Roman Catholic District of Wales, being consecrated as a bishop on 28 October.
8 October - Taff Vale Railway is officially opened, the first steam-worked passenger railway in Wales, running from Cardiff docks to Navigation House at Abercynon via the Cardiff station known in modern days as Queen Street. Public service begins the following day.
30 October - First branch of the Church of Jesus Christ of Latter-day Saints in Wales formed in Flintshire.
18 November - The paddle steamer City of Bristol is wrecked at Llangennith, Gower, drowning about 22 people.
Approximate date - Rebuilding of Gregynog Hall with extensive use of concrete begins.

Sir John Hanmer - Memorials of the Parish and Family of Hanmer
William Lloyd - ''The Narrative of a Journey from Cawnpoor to the Boorendo Pass''