Under the 2023 review, the constituency was defined as being composed of the following as they existed on 1 December 2020: • The
County Borough of Bridgend wards of: Bettws; Blackmill; Blaengarw; Llangeinor; Nant-y-moel; Ogmore Vale; Pontycymmer. • The
County Borough of Rhondda Cynon Taf wards of: Cwm Clydach; Cymmer; Ferndale; Gilfach Goch; Llwyn-y-pia; Maerdy; Pentre; Pen-y-graig; Porth; Tonypandy; Tonyrefail East; Tonyrefail West; Trealaw; Treherbert; Treorchy; Tylorstown; Ynyshir; Ystrad. Following local government boundary reviews which came into effect in May 2022, the constituency now comprises the following from the 2024 general election: • The
County Borough of Bridgend wards of: Blackmill; Garw Valley; Nant-y-moel; Ogmore Vale. • The
County Borough of Rhondda Cynon Taf wards of: Cwm Clydach; Cymmer; Ferndale and Maerdy; Gilfach-goch; Llwyn-y-pia; Pentre; Pen-y-graig; Porth; Tonypandy; Tonyrefail East; Tonyrefail West; Trealaw; Treherbert; Treorchy; Tylorstown and Ynyshir; Ystrad. The parts in Rhondda Cynon Taf comprise the whole of the former constituency of
Rhondda plus the community of
Tonyrefail, transferred from
Pontypridd. The parts in the Bridgend County Borough were previously part of the abolished constituency of
Ogmore. ==Election results==