Interior
Single-cell plan with continuous nave and chancel. Six-bay arched-braced collar truss roof, of thin scantling with bolted braces. The trusses appear to have originally been of tie-beam and raking strut type, and probably relate to the 1777 restoration; the arched braces appear to be 1860s additions. Plain pine pews on raised wooden plinths and with central counter-changed red/black tiled pavement. Octagonal Perpendicular-style font on stone pavement section towards W end. Of limestone, this has an octagonal plinth and base and wooden font cover with decorative ironwork. Semi-octagonal pulpit of pine with simple open tracery panels to the front; this has a chamfered, tooled limestone plinth with a flight of 3 wooden steps from the S.
The chancel is contained within the eastern-most bay and has a stepped-up pavement; pine altar rails with scrolled ironwork supports. Carved oak reredos in early Decorated style with crenellated brattishing and both zoomorphic and foliated brackets. Crocketted and gabled panels flank the E window group; blind Y-tracery with rosettes, carved geometric decoration and blind quatrefoils below. On the jambs flanking the central E window are placed carved female saint sculptures, on column bases with small canopy niches. Polychromed tiled dado in octagonal framed arrangements, with 2 on either side of the central altar; these bear the Alpha and Omega symbols, together with Christ's monograms. The reredos is inscribed (on the dado rail) with a dedication to 'Katherine Rawlinson, wife of Meilir Owen, Tan-y-Gwrt,' and is dated 1870.
Monuments: on the N wall is a simple classical funerary tablet of limestone on a black coloured base: to Frances Roberts of Mysevin, d.1831, Mary, d.1835, Mary, also d.1835 and Joseph, d.1835. On the same wall is a simple white marble tablet (on a black coloured limestone base) to Margaret Edwards of Plas Nantglyn, d.1835.
Glass: triple lancet E window group with figurative glass in Decorated style, showing scenes from Christ's Passion; by O' Connor, signed and dated 1861. Three S windows are in memory of Katherine Rawlinson (as is the retable), and were installed in 1872; they depict figurative scenes of charitable acts. The western-most southern window is dedicated to Ellen Owen, 1895, and is signed 'Alexander Gibbs and Co., Bloomsbury St., London.' Finally the W rose window depicts SS Peter, Paul, John and James, each within his own quatrefoil panel: in memory of Jane, wife of Aneurin Owen, 1877.
Adjoining the N side at the W end, and accessed from the church via a plain boarded door is a vestry. Within is an C18 incised slate benefactors' board, together with an early inscribed stone.