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.

For Westminster purposes, the same boundary change became effective for the 2010 United Kingdom general election.

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

Since the 2007 Assembly election, the region includes Aberconwy, Alyn and Deeside, Arfon, Clwyd South, Conwy, Delyn, Vale of Clwyd, Wrexham and Ynys Môn.

Additional member seats are allocated from the lists by the d'Hondt method, with constituency results being taken into account in the allocation.