An earth mound, visible in fields to the south of the Prestatyn railway station, near Nant Hall, marks the site of an early wooden motte and bailey castle. Prestatyn Castle occupies a low-lying position, but still commands a view across much of the flat coastal plain and guarded the coast road between Rhuddlan and Chester. It consists of the remains of a motte c.20m in diameter with surrounding ditch, and a bailey which, unusually, encloses the whole of the motte. Excavation in about 1913 revealed a substantial stone wall 1.2m thick surrounding the bailey, inside its ditch, but no trace of a structure on the motte. A slightly raised causeway approaches from the south (away from the railway), but no detail is now visible where it meets the bailey; there is no obvious entrance gap in the motte ditch.