Caerphilly (UK Parliament constituency)

Caerphilly (Caerffili) is a constituency centred on the town of Caerphilly in South Wales, represented in the House of Commons of the UK Parliament since 2024 by Chris Evans of the Labour Party.

Since its creation, the constituency has always elected Labour MPs, although the predecessor constituency of East Glamorganshire, and prior to that Glamorganshire had elected Liberal MPs throughout the Victorian era.

Boundaries
The Caerphilly constituency covers roughly the southern and eastern half of Caerphilly district, the part of the district historically located in Glamorgan. In the northwestern portion of the constituency are communities such as Hengoed and Ystrad Mynach, extending in a southeasterly direction through Caerphilly and Llanbradach to the rural outcrops bordering Cardiff.

At the 2023 Periodic Review of Westminster constituencies and under the June 2023 final recommendations of the Boundary Commission for Wales for the 2024 United Kingdom general election, the constituency retained its name but its boundaries altered. Four wards were taken from the abolished Islwyn constituency.

2010-2024: The Caerphilly County Borough wards of Aber Valley, Aberbargoed and Bargoed, Bedwas and Trethomas, Gilfach, Hengoed, Llanbradach, Machen and Rudry, Morgan Jones, Nelson, Penyrheol, St Cattwg, St Martins, Van, and Ystrad Mynach.

2024-present: The Caerphilly County Borough wards of Aber Valley, Bedwas and Trethomas, Cefn Fforest and Pengam, Hengoed, Llanbradach, Machen and Rudry, Maesycwmmer, Morgan Jones, Nelson, Penyrheol, Pontllanfraith, St Cattwg, St Martins, Van, Ynysddu, and Ystrad Mynach.

Elections in the 2010s
Of the 81 rejected ballots:
 * 59 were either unmarked or it was uncertain who the vote was for.
 * 22 voted for more than one candidate.

Of the 160 rejected ballots:
 * 132 were either unmarked or it was uncertain who the vote was for.
 * 28 voted for more than one candidate.

Elections in the 2020s
Of the 156 rejected ballots:


 * 127 were either unmarked or it was uncertain who the vote was for.
 * 28 voted for more than one candidate.
 * 1 had writing or a mark by which the voter could be identified.