St Mary's Church is located prominently on the Lenten Pool roundabout, set back slightly behind low curving forecourt walls.
A large stone-built aisled church with tower in an eclectic Victorian Gothic style, intended as a replacement for the medieval St Hillary's, near the castle, the foundation stone laid in 1871. It was was designed by Lloyd Williams and Underwood, architects of Denbigh, and completed in 1874 when it was opened for service though consecration did not take place until December 1875. The delay was caused by a law suit over the reredos, designed by Lloyd Williams and executed by Earp of Lambeth, which was considered by many (including the bishop) as 'too Catholic in taste' and caused considerable controversy until it was (grudgingly) modified.
The ground plan comprises chancel, choir with aisles (the north for organ chamber and vestry, the south appropriated for scholars of Howell's School), nave with north and south aisles of five bays, a cloistered porch at the west end , and a lofty tower at the south transept. The material is light coloured local limestone, irregularly pointed, with dressings from the Minera quarries. The parapet of the tower is set off with rich crocketts and finials, and within it a peal of eight bells. Internally, the chancel which is raised above the the level of the nave and divided into choir and sacrarium, is handsomely furnished with carved oak seats, rich altar rails and standards, and is paved with encaustic tiles. The reredos, carved in Caen stone, is divided by marble shafts into three compartments, surmounted by rich ornamentation of finials, crockets and angel figures.
Sources:
D.R.Thomas, History of the Diocese of St Asaph vol.2 (1911), p.22-4.
Cadw Listing database

David Leighton & Geoff Ward, RCAHMW, 7 October 2014