; ) is a six-member constituency of the Senedd (Welsh Parliament; ) used in the 2026 Senedd election. It covers areas in the south-east of Wales, particularly parts of Merthyr Tydfil and Rhondda Cynon Taf.
It was proposed following the 2026 review of Senedd constituencies, and was a pairing of the two UK Parliament constituencies of Merthyr Tydfil and Aberdare and Pontypridd. It has a Welsh-only name.
Boundaries A Senedd constituency comprising the boundaries of the UK Parliament constituencies of Merthyr Tydfil and Aberdare and Pontypridd, has been proposed by the Democracy and Boundary Commission Cymru for the 2026 election to the Senedd (Welsh Parliament; ). It was initially proposed using the English name Merthyr Tydfil, Aberdare and Pontypridd in September 2024, but was renamed to in December proposals with most constituencies using Welsh-only names. It was then given the Welsh-only name and its boundaries were confirmed in the commission's final recommendations in March 2025. When announcing their candidates, Reform UK used "Merthyr Tydfil and Aberdare, Pontypridd" instead, using the English names for the pair of UK Parliament constituencies that form it.
It encompasses parts of the principal areas (county boroughs) of Merthyr Tydfil County Borough and Rhondda Cynon Taf in South Wales. The constituency was established in 2026, following the passing of the Senedd Cymru (Members and Elections) Act 2024. The act legislates electoral reform of the Senedd to create 16 larger "super constituencies", pairing the 32 UK Parliament constituencies in Wales, and using a new fully proportional voting system, with each constituency electing six Members of the Senedd (MSs) rather than one previously. Members of the Senedd Term Election Distribution MS MS MS MS MS MS 7th 2026 3 1 2 Heledd Fychan(PC) Jason O'Connell(Ref) Lis McLean(PC) David Hughes(Ref) Sara Crowley(PC) Vikki Howells(Lab)
Elections Elections in the 2020s
2021 notional result Party Vote % Seats Labour 32,067 52.5 4 Plaid Cymru 12,061 19.7 1 Conservative 9,681 15.8 1 Abolish 1,836 3.0 0 Independent 1,468 2.4 0 Liberal Democrats 1,386 2.3 0 Reform UK 1,040 1.7 0 Propel 816 1.3 0 Green 464 0.8 0 UKIP 304 0.5 0
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