Also, however, it is one of nine constituencies in the North Wales electoral region, which elects four additional members, in addition to nine constituency members, to produce a degree of proportional representation for the region as a whole.

Part of its area was transferred to the Montgomeryshire constituency, in Powys.

For Westminster purposes, the same boundary changes became effective at the 2010 United Kingdom general election.

As created in 1999, the North Wales region includes the constituencies of Alyn and Deeside, Caernarfon, Clwyd West, Clwyd South, Conwy, Delyn, Vale of Clwyd, Wrexham and Ynys Môn.

For the period 1999 to 2007, the Clwyd South constituency can be described as consisting of electoral divisions as follows: In general elections for the Senedd, each voter has two votes.