Double-chamber plan with no architectural division between the nave and chancel spaces. Both chambers have exceptionally fine 10-bay late C15/early C16 hammerbeam roofs. These have moulded principals, purlins and rafters, with crenellated brattishing and octagonal piers to the wall posts. The hammerbeams correspond to the bay divisions and each has an intermediate arch-braced collar truss, each with fine human and animal carvings above the wall plate. The N and S chambers are divided by an elegant 5-bay Perpendicular arcade, with moulded Tudor arches springing from octagonal columns with moulded bases and abaci. On each face of the arcade is a continuous label with large stop carvings at each bay division. These are of animals and shield-bearing angels; similar zoomorphic, foliate and heraldic boss carving to the stone wall plate, all now (regrettably) with bright modern polychromy. Slate-flagged floors to both chambers, including many C17 and C18 tombslabs, and parquet flooring to the central and side seating sections. The S chamber has a plain octagonal font of tooled limestone dated 1640. Squat octagonal base with chamfered plinth on a modern concrete base; simple early C20 oak font cover. Panelled octagonal oak pulpit (again, S chamber) with tall panelled back and sounding board with moulded cornice. The back panels bear the incised inscription: 'R.P. H.B: Wardens 1683'. Modern organ at the W end of the N chamber.
The nave is separated off from the chancel by a Perpendicular-style carved oak screen which extends across both chambers and returns on the N side of the arcade to separate the chancels of each chamber. By C Hodgson Fowler, 1908, although incorporating a small number of elements (mostly tracery heads) from a former (apparently early Tudor) Rood screen. Plain dado with wide Tudor-arched entrances and flanking bays of open tracery; that to the N has a bracketed canopy. Pierced, cusped tracery heads and fine vinescroll carving with surmounting brattishing to the beam; panelled half-gates to each entrance, with open tracery upper sections and brattishing to the top rails.
The (present) chancel is on the N side. This has simple Perpendicular-style oak choir stalls of similar date, with blind tracery arcading to the front panels. Stepped-up sanctuary with plain early C20 oak rails. Simple plain-panelled oak retable with brattishing; vertically-panelled flanking sections with simply-moulded rail and blind tracery detailing. The chancel to the S chamber has a stepped-up sanctuary with finely-carved oak altar table dated 1628. This has strapwork relief-carving to the frieze and bottom rails, the former with angel busts flanking a central angel carving; bulbous carved legs. Tall contemporary altar rails with turned oak balusters supporting an exuberantly-carved vinescroll rail, the latter no doubt originally part of the Rood screen. The altar rails return to the rear and abut a tripartite panelled retable. This is made up out of sections of late C17 fielded panelling, doubtless reused from former box pews.
Monuments: Chancel, N chamber: on the N wall is an exceptionally fine and important Renaissance wall monument to Humphrey Llwyd of Foxhall, d.1568. The monument is of aedicular form and consists of an alabaster relief depicting Llwyd kneeling within a vaulted classical interior with his heraldic achievements in the tympanum above. This is contained within a round-headed inner arch of tooled limestone, itself supported by winged puti and contained within an outer frame with Corinthian columns supporting an entablature and moulded pediment; Renaissance frieze carving and grotesques. Surmounting the pediment is a large ball finial in the form of a terrestrial globe, a reference to Llwyd's cartographic interests and his contribution to Ortelius' 'Theatrum Orbis'. Below the monument is an inscribed memorial stone, inset into the wall.
Immediately to the W of the Llwyd monument is a fine brass to Richard Middleton, MP, Constable of Denbigh Castle, d.1575. The brass has engraved portraits of Middleton and his wife kneeling, accompanied by their nine sons and seven daughters and with the Middleton and Dryhurst arms above. Guilloche decorated border and a long inscription in gothic letters; moulded (black-painted) stone frame with flanking columnar shafts. To the R of the Lloyd monument is a large classical mural tablet to Robert Salusbury of Cotton Hall and family (d.1774, erected 1802). Of white and grey figured marble with moulded cornice, apron and flaming urn and shallow obelisk to the top. On the E wall is an heraldic stone cartouche with the finely-carved arms of the Salusbury family of Lleweni; polychromed.
Chancel, S chamber: this contains the famous tomb of Sir John Salusbury of Lleweni, Chaimberlain of North Wales, and his wife Dame Joan. The monument consists of a very fine alabaster tomb chest with life-sized recumbent effigies (that of Sir John in full armour, that of Dame Joan in long robes and high ruff), with carved figures of their nine sons and four daughters as weepers. The tomb was erected in 1588, ten years after Sir John's death, by Dame Joan, as recorded in an inscription around the cornice; it is known to be by the sculptor Donbins and retains the majority of its original polychromy.
On the S wall is a large Baroque wall monument to Sir Robert Cotton, Bart, and his wife, the Lleweni heiress, Lady Hester Salusbury; erected 1715 and attributed to the workshop of Edward Stainton. Of white and grey figured marble with selective gilding and polychromy, the monument consists of a swagged inscription tablet set in an architectural frame, the segmental moulded and coffered pediment to which is supported on Solomonic columns with Corinthian capitals; flanking garland volutes and consoled base with winged angel relief carvings to the apron, with laurel-wreathed foundation plaque below. Large surmounting flaming urn flanked by fine heraldic cartouches. On the E wall (to the R of the window) is a small baroque mural monument to Mary Dryhurst and John Roberts, mason, possibly by the latter, c1692. This is in the form of a fictive drapery banner with heraldic cartouche above and a winged, wreathed angel below; inappropriate modern polychromy. Below the S window is a life-sized recumbent relief of Jeanette Octavia Ward (d.1913) with attendant angels; of grey marble and by the sculptor Albert Toft, 1915.
Nave, N chamber: large Baroque monument to Thomas Shaw and family, Recorder of Denbigh (d.1717); of white and grey figured marble. Draped tablet with flanking panelled pilasters supporting a moulded segmental pediment; flaming urn finial with flanking heraldic cartouches. To the L are two classical mural tablets to Sarah (L) and Richard (R) Heaton, of Plas Heaton, who died in 1814 and 1791 respectively. By Richard Westmacott the elder, in white and black marble. Both have obelisks with draped urns. Above these is a Grecian tablet of white marble in the form of a squat obelisk; to Elizabeth, wife of John Heaton, d.1822. Next (W) is a simple tablet in black and white marble to Richard Clough of Glan-y-Wern (d.1784) and family; last date 1838. On the NW wall is a small classical tablet of white and grey marble to Thomas Edwards, the bard 'Twm o'r Nant' (1739-1810); framed Welsh inscription tablet with plain apron and a surmounting obelisk with relief-carved muse figure holding an oval portrait bust of the deceased.
The nave S chamber has 3 simple classical tablets of white marble to members of the Twiston family of Henllan Place (1837-53).
Stained and painted glass: the S chamber E window has a large cycle of figurative glass showing scenes from Christ's Passion in Arts and Crafts style; a Harrison family memorial window dated 1918. The N chamber N chancel window is an Arts and Crafts figurative window of 1912 in memory of Eliza Vaughan Jones of Park House; depicting the Marys at the Sepulchre. In the porch window are various jumbled fragments of late C15 or early C16 glass, presumably originating in one of the E windows.
Hatchments etc. five late C18/early C19 hatchments in the N nave and four similar hatchments in the S; all of conventional lozenge shape and with fine heraldic painting (Salusbury, Middleton, Heaton and other families). On the S wall is a further, smaller rectangular hatchment to Mrs Anne Lloyd of Plumog (sic), dated 1686. This has a painted inscription on panel with arms above. On the W wall (S) is a large, framed benefactors' board, with painted inscriptions and the date 1720 together with churchwardens' names Hugh Price and William Hillditch (on the apron). Two framed wooden tablets in the N chamber record the gift of land by Hugh Robert Hughes of Kinmel Park in 1858 and 1889. On the W wall (N) is a framed wooden tablet of 1781 recording the gift of church plate by the Rev. Robert Middleton.
In the N chancel is a fine brass chandelier of 2 tiers and 12 branches inscribed: 'The gift of Mrs Ann Moreton. John Thomas, Chester, fecit 1753.' Oak and iron-bound church chest inscribed: 'TW DD Wardens 1676.' In the S chancel stands a large bronze bell (formerly in the tower).