Preseli Pembrokeshire is a constituency of the National Assembly for Wales. It elects one Assembly Member by the first past the post method of election. Also, however, it is one of eight constituencies in the Mid and West Wales electoral region, which elects four additional members, in addition to eight constituency members, to produce a degree of proportional representation for the region as a whole.
The constituency was created for the first election to the Assembly, in 1999, with the name and boundaries of the Preseli Pembrokeshire Westminster constituency. It is a Dyfed constituency, one of five constituencies covering, and entirely within, the preserved county of Dyfed.
The region consists of the eight constituencies of Brecon and Radnorshire, Carmarthen East and Dinefwr, Carmarthen West and South Pembrokeshire, Ceredigion, Llanelli, Meirionnydd Nant Conwy, Montgomeryshire and Preseli Pembrokeshire.
Boundaries changed at the 2007 Assembly election. Preseli Pembrokeshire remained one of five Dyfed constituencies and one of eight constituencies in the Mid and West Wales region. However, boundaries within Dyfed have changed to realign them with local government ward boundaries and to reduce disparities in the sizes of constituency electorates, and the boundaries of the region will change, to align them with the boundaries of preserved counties.
The region consists of the constituencies of Brecon and Radnorshire, Carmarthen East and Dinefwr, Carmarthen West and South Pembrokeshire, Ceredigion, Dwyfor Meirionnydd, Llanelli, Montgomeryshire and Preseli Pembrokeshire.
For Westminster purposes, the same new constituency boundaries will become effective for the next United Kingdom general election.
In general elections for the National Assembly for Wales, each voter has two votes. The first vote may be used to vote for a candidate to become the Assembly Member for the voter's constituency, elected by the first past the post system. The second vote may be used to vote for a regional closed party list of candidates. Additional member seats are allocated from the lists by the d'Hondt method, with constituency results being taken into account in the allocation.