Double-naved interior with 10-bay roofs to both chambers. These are fine Perpendicular examples, with alternating arched-braced collar and hammerbeam trusses. The latter have, for the most part, lost their wall posts; the former are carried on carved figures or heads, some retaining early gilding; moulded principals and purlins. The two chambers were formerly divided by an 8-bay stone arcade, the engaged piers to which survive at the E and W ends. The present arcade consists of a series of narrow fluted wooden pillars which rise from the octagonal bases of its predecessor.
The 2 western-most bays of the nave have slate-flagged floors to both chambers; the remainder is stepped-up and has a simple decorative C19 tiled floor to the N (black, red and yellow lozenge decoration) and further slate flagstones to the S side; these include some sandstone gravestones, mostly of late C17 and C18 date. Mid C19 fixed pine pews flank the central arcade along the N and S sides. Along the N wall of the N aisle however, are fixed pews of oak and pine, made up in the C19 out of earlier (mostly early C18) fielded panelling. Similar fielded panelling runs along the dado on the N and S walls. Towards the W end of the N chamber is a Perpendicular limestone font basin. This is of conventional octagonal type, with blind quatrefoil tracery decoration to each face; C19 octagonal sandstone base. Fine second-quarter or mid C17 oak pulpit with geometric panelled decoration to main sides between tiers of blind arcading; columnar balusters above and below, and a dentilated cornice. C19 pine stair with turned newel and balusters. The N chamber has a 16-branch 3-tier wooden candelabrum (originally of 24 branches), with the original pale green paint finish and the painted inscription 'The Gift of the Reverend Mr. Rutter, 1749.'
The chancel occupies the E end of the N chamber. This is stepped-up with pavement as before. C19 choir stalls of oak and pine, incorporating carved fielded and inscribed panelling from broken-up C17 and C18 box pews. Amongst these are sections with names, initials and the dates 'March 26th 1613, 1670, 1713, SR 1721', and 'Sedes Guiliemi Platt de Rhydonnen...Gen, Aug XV NO MDCCXIII.' On the N side, at the E end, is a section of oak panelling with 10 fine relief-carved panels and the date 1570 (the latter associated, but added); this, until the late C19, formed the back of a bench, though is regarded as being of secular origin, traditionally from Bachymbyd Fawr. Mid C18 oak reredos with central and outer fluted pilasters, inlaid decoration and moulded, dentilated cornice. The 2 eastern bays of the S chamber are partitioned-off to form a small chapel (modern partitioning encasing that of the C19).
Monuments: Nave, N chamber: at the W end are the reconstructed fragments of an early C14 ecclesiastic's effigy, lying on a concrete chest tomb incorporating 5 contemporary headless weepers. Nearby is a fine sepulchral stone cross of the mid C14; hexagonal, with relief-carvings of a bishop and Christ on the Cross to its respective sides. On the N wall is a framed Gothick mural tablet to Peter Ellis Eyton of Ty Isaf, MP for Flintshire, d.1878. Nave, S chamber: fine, large Royal Arms hatchment on the S wall (unframed); dated 1661 and known to have been painted by a Mr Hill for the sum of £6. To the R of this is a C19 funerary hatchment with the arms of Mrs Edwards (of Cerrigllwydion Hall), d.1859. Beyond this is a C17 stone funerary tablet to Edward Lloyd of Berth Lloyd, with Latin inscription. Towards the W end are 2 large framed wooden benefactors' boards, one dated 1787, the other contemporary. S chapel: flanking the E window are two classical mural tablets, that to the L to Edward Edwards of Cerrigllwydion d.1816, and that to the R to his wife Lowry d.1807. Both are of white and grey marble, and each has an inscription tablet surmounted by a draped urn; obelisk back panels, and aprons, that to the R with polychromed heraldic shield. On the S wall is a similar white marble mural monument to the Rev. William Williams Edwards of Cerrigllwydion d.1829 and his wife; relief-carved Grecian muse with draped urn and column. To the R of this is a C19 framed funerary hatchment bearing the arms of the Rev Edwards.
Wall Paintings: at the western end of the N chamber, on the N wall, is a fine and large wall painting depicting St Christopher; secco, second-quarter or mid C15. Further to the E is a small relocated wall painting fragment of Welsh Black Letter Gothic text (detached from its original location, overlying the St Christopher); early C17. Above the S door is a (repainted) mural inscription 'R Hughes John Evans 1677' (churchwardens).
Stained and painted glass: C18 coloured glass to the tracery lights of the E window (N chamber); mid Victorian figurative glass to the chancel N window. In the S chapel is a window with figurative glass erected by Mrs Williams Edwards of Cerrigllwydion in 1855.