1997–2010: The Borough of Rhuddlan, the District of Glyndwr wards of Denbigh Central, Denbigh Lower, Denbigh Upper, Henllan, and Llandyrnog, and the Borough of Colwyn ward of Trefnant.
2010–2024: The Denbighshire County electoral divisions of Bodelwyddan, Denbigh Central, Denbigh Lower, Denbigh Upper/Henllan, Dyserth, Llandyrnog, Prestatyn Central, Prestatyn East, Prestatyn Meliden, Prestatyn North, Prestatyn South West, Rhuddlan, Rhyl East, Rhyl South, Rhyl South East, Rhyl South West, Rhyl West, St Asaph East, St Asaph West, Trefnant, and Tremeirchion.
The seat was won by the Labour candidate in 1997, 2001, 2005 and on a marginal majority in 2010. The seat was next won by the Conservative candidate standing in 2015. The 2015 result gave the seat the 4th most marginal majority of the Conservative Party's 331 seats by percentage of majority.[3] However, Labour regained the seat in the 2017 general election with more than half the eligible votes, the first Labour gain from the Conservatives on the night. In 2019 general election, the seat reverted to the Conservatives as the party made gains from Labour in north east Wales.[4]