Carmarthen East and Dinefwr was a constituency of the House of Commons of the Parliament of the United Kingdom last represented since 2010 by Jonathan Edwards of Plaid Cymru. It elected one Member of Parliament (MP) by the first past the post system of election. It was created in 1997, mostly from the former seat of Carmarthen. The Carmarthen East and Dinefwr Senedd constituency was created with the same boundaries in 1999 (as an Assembly constituency). The constituency was abolished as part of the 2023 Periodic Review of Westminster constituencies and under the June 2023 final recommendations of the Boundary Commission for Wales. Its wards were divided between Caerfyrddin (Carmarthen) and Llanelli.

Boundaries

The constituency was within the Carmarthenshire authority area, with Llanybydder, Llandovery and Llanfihangel-ar-Arth in the north, Llanfihangel-uwch-Gwili, Llanegwad, and Llandeilo in the central area, and Ammanford and Glanamman in the south. Boundary changes for the 2010 general election introduced minor alterations, with the areas around Hermon and Llanpumsaint removed to the Carmarthen West and South Pembrokeshire constituency. These changes came into effect in 2007 for the National Assembly for Wales. The constituency includes the whole of 41 Carmarthenshire communities (Abergwili; Ammanford; Betws; Cenarth; Cilycwm; Cwmamman; Cynwyl Gaeo; Dyffryn Cennen; Gorslas; Llanarthney; Llanddarog; Llanddeusant; Llandeilo; Llandovery; Llandybie; Llandyfaelog; Llanegwad; Llanfair-ar-y-bryn; Llanfihangel Aberbythych; Llanfihangel-ar-Arth; Llanfihangel Rhos-y-Corn; Llanfynydd; Llangadog; Llangathen; Llangeler; Llangunnor; Llangyndeyrn; Llanllawddog; Llanllwni; Llansadwrn; Llansawel; Llanwrda; Llanybydder; Llanycrwys; Manordeilo and Salem; Myddfai; Newcastle Emlyn; Pencarreg; Quarter Bach; St Ishmael; Talley).

Members of Parliament

Elections

Elections in the 1990s

Elections in the 2000s

Elections in the 2010s

Of the 65 rejected ballots: Of the 145 rejected ballots: Edwards was elected as a Plaid Cymru MP, but had the whip withdrawn by the party after he was arrested on suspicion of assault in May 2020.