Single-cell plan, with continuous nave and chancel. Fine late C15 seven-bay roof consisting of moulded, arched-braced collar trusses with cusped trefoil decoration, stopped-chamfered purlins and cusped windbraces in two tiers. Fixed mid C19 pine pews (1851), with panelled ends and pew doors. These flank a contemporary geometric tiled pavement to the nave centre. Good early C18 oak W gallery supported upon 2 simply-moulded posts. This has stopped-chamfered ceiling joists and retains its original oak boarded gallery floor. On the S side is a simple oak stair with original narrow, turned balusters, oak treads and risers. Renewed C19 baluster newel and moulded rail; panelled understair with 4-panel, mid C19 pine door. Turned balusters to moulded gallery balustrade rail with inscription in raised letters to its front face: 'TP TL Church Wardens 1721'. The northern third of the space, below the gallery, is occupied by an office/vestry. This was formed in 1957 by partitioning the E and S sides; these are each of 5 bays and have pointed-arched heads and simple mullions to glazed upper sections; entrance via twin doors to S side. Plain octagonal font of Perpendicular style and conventional type; C19 with C20 oak font cover. Octagonal mid C19 pulpit with deep Perpendicular-style panels to each face; moulded cornice on an octagonal base. The chancel is stepped-up and is separated from the nave by a fine late C15 Perpendicular Rood screen. This is of 9 bays with a wide Tudor-arched central opening flanked on each side by 4 narrower bays. Panelled dado with moulded stiles and fine blind tracery on the S side (lost to the N). The dado rail has relief-carved rosette motifs and wyvern and 'Green Man' carvings to either side of the central opening. The upper section of the screen is open and has complex pierced tracery heads incorporating (to the far R) a portcullis motif, an early Tudor badge; moulded Rood beam with relief-carved vinescroll decoration. The chancel roof (consisting of the last 2 bays of the continuous Nave-chancel roof) also has vinescroll decoration to its purlins. The choirstalls are similar to, and contemporary with, the nave pews; Gothic reading desk with moulded base and rail, and 5-bay open tracery front, with cusped, pointed arches. The sanctuary is stepped-up and boarded, and has contemporary altar rails with cusped iron tracery supports; C19 dado panelling with blind arcading in two tiers. Carved wooden reredos by Bodley and Hare of London, 1927. This is in the form of a relief-carved triptych with central recessed Crucifixion and flanking niches containing the carved figures of the Virgin and St John the Evangelist; ogee tracery heads to canopies and crenellated brattishing to cornice.
Stained and Painted Glass: fine C16 decorative quarries to the eastern nave window on the S side, depicting acorn and oakleaf badges in yellow stain. The E window was donated in 1857 as a memorial to John Williams, MP, and depicts scenes from Christ's life by Clayton and Bell with elaborate borders by Powell and Sons of London; 2 further windows by Powell, given by George Johnson of Plas Llanrhydd, Esq appear on the chancel S and Nave N sides. In the N wall (W end) is a fine 3-light window depicting the Transfiguration, erected in memory of Thomas Downward, of Bathafarn Park, Esq, d.1859.
Monuments: Chancel, N wall (E to W): a fine, large-scale funerary monument in polychromed stone and marble to John and Jane Thelwall of Bathafarn Park, d.1586 and 1585 respectively. The monument consists of sculpted representations of the couple shown kneeling within a twin-arched architectural frame, with Corinthian columns supporting a classical entablature; surmounting this is a large heraldic cartouche. Below the main figures are placed fourteen smaller sculpted figures, depicting the couple's ten sons and four daughters, each inscribed with his or her name. Below this is a scrolled apron incorporating a framed black marble inscription tablet. The polychromy is original and survives in good condition. Next to this is a monument to the latter's ninth son, Ambrose Thelwall (1570-1653), Yeoman of the Robes to King James 1st, King Charles 1st and Prince Charles (later Charles II). This is in the form of a fine polychromed, life-sized bust set upon a classical plinth with swagged and voluted sides and incorporating a black marble inscription tablet; the plinth is of painted plaster. The bust is set in front of a segmentally-arched niche formed by blocking a C15 chancel window; above this is a good contemporary and associated heraldic cartouche. The polychromy is original and survives in especially good condition. Next to this is a fine white marble wall memorial to John Thelwall of Bathafarn Park, Esq, d.1664. This is in the form of a draped tablet with surmounting polychromed heraldic shield, supported by winged putti. Immediately to the L of this is a similar monument to his son, also John Thelwall, a Barrister-at-Law, who died in 1686; swagged banner format, in white marble, with good polychromed shield above. Below this is a smaller lozenge-shaped tablet addition to Anne, his widow, d.1712, attributed to Robert Wynne of Ruthin. This has swags, trumpets and foliate decoration in shallow relief, together with a winged putto- head.
The E end (L of the E window) has a Grecian classical memorial tablet to Anne Jemima Clough, of Bathafarn Park, d.1812; by Sir Richard Westmacott, RA. Of white marble on a black marble base. Above this is a simple classical tablet in white and black marble to Sarah Downward of Bathafarn Park, d.1829. On the other side of the E window, occupying the SE corner, is a double monument to Rowland White, 'late Baron of ye Exchequer for North Wales', d.1670. This consists of a pair of black marble tablets contained within fine architectural frames of painted plaster, now somewhat eroded. Each has a heavily-moulded broken pediment with central (polychromed) heraldic cartouche and flanking gadrooned urns; swagged, panelled sides with volutes. A winged putto head is placed at the junction between the two, in the corner.
Chancel, S wall (E to W): black marble mural tablet to Robert and Mary Price, erected 1777; draped urn in white marble above. To the R of this is a simple oval mural tablet to Jane and Maurice Jones of Gellygynnan, d.1784 and 1785 respectively; of white marble on a rectangular black and white marble frame, with surmounting urn in relief.
Nave, N wall (E to W): large white marble tablet to Eubule Roberts of Llanrhydd House, Esq, d.1765, together with his descendants. This has a simple frame with grey/white mottled marble sides surmounted by a broad obelisk with an applied urn base (the urn itself missing at the time of survey); swagged apron with a central wreathed shield (blank). Next is a fine baroque wall monument to Thomas Roberts d.1708, with a smaller additional monument to his wife Anne Thelwall d.1746 attached below. The main monument is attributed to Robert Wynne of Ruthin; it is in white marble and takes the form of an oval cartouche with fine relief-carved detailing, including volutes, swags, draperies and cherubs. The subsidiary monument, below, is a draped tablet with flanking trumpets. To the L of this is a simple tablet to John Price of Tyn-Coed, d.1782; of polished black slate with shaped top. Nave, S wall (E to W): white on black marble mural tablet to Georgina Neville, d.1843, by M W Johnson of London; shaped top with rose and sickle relief carving. Next is a series of four simple classical tablets to members of the Jones family, all white on black marble: firstly Hugh Jones of Woodlands, d.1855; then the Rev Hugh Jones of Caer Groes, d.1825; next Roger Jones of Caer Groes, d.1797, and finally Rachel and Henry Jones of Plas Tourbridge, d.1838 and 1842. The latter is by J Blayney of Chester. At the W end are two early C19 framed almsboards and a further commemorative board dated 1852.