Cefn Meiriadog (sometimes Cefnmeriadog) is a rural community in Denbighshire, Wales, just south-west of the city of St Asaph.

It is said that the place was named for St Meiriadog, a 4th or 5th century Breton saint.

Cefn Caves are nearby, where human and early Neanderthal remains dating back 250,000 years have been discovered.

About 300 metres SE of the fort Bryn y Cawr ("Giant's Hill", at the SE end of the ridge) stands the small St Mary's church (Grade II listed).

1865, made up of two "townships": Wigfair and Meiriadog (both in Denbighshire), previously part of St Asaph parish.