Interior
A spacious interior, divided by a squat 4-bay arcade of depressed 4-centred hollow-chamfered arches of typical Caernarfonshire type, set on octagonal columns. The S nave is of eight and a half roof bays; low pitched arched braced collar trusses and exposed rafters supported by two tiers of purlins. The walls are plastered and the floor quarry-tiled. The nave is of nine and a half bays of arch-braced collar trusses with cusped raking struts, probably C15. The walls are similarly plastered and the floor tiled. At the centre, a 7-bay rood screen of the C15 or early C16 with a moulded head bressumer and stanchions, and fleurons on the lower rail, the inserted arches including those to the central door now missing. It has on its E side, two late medieval benchends, each topped with a carved and much worn crouching animal and a monstrous bird. The screen bears much faded paintwork. A vestry is divided off at the W end by matchboard partitions.
Glass: E window, a Crucifixion of 1917 in memory of Lieut. David Davies.
Fittings: the S nave Altar is raised over 2 steps, and has a C17 turned communion rail; the N nave Altar is C20, with an oak communion rail and reredos; font, an octagonal sandstone bowl with a scalloped lip, raised on an octagonal stem; pulpit, part octagon, early C19, with brass oil lamp bracket. By the S door, a poor box, probably of the C17, in the form of a hollowed octagonal post on a short stem, although it is said to have been placed here by command of Henry II in 1166 for donations towards the crusades.
Monuments: S Nave, east wall, (a) Carrara marble scroll on slate, to William Cadwaladr Jones of Llwyn-onn, d.1916 on the S.S.Gangarion; on the arcade (b) a small slate plaque reading PLACE LLANARMON T. IM. 1763 2 GRAVES; below the wooden floor, four ledger slabs, (c) Jane Winn, widow of Owen Hughes of Newborough, d.1686; (d) Richard Wynne, infant son and heir to William Wynne of Llanfair, d.1727; (e) Elizabeth Williams, widow and eldest daughter of Francis Lloyd of Llangwynnadl, d.1749, and (f) Ellin Parry, daughter and heiress of Hugh Wynne of Penarth, widow of Love Parry of Cefn Llanfair, mother of Love Parry of Wern-fawr and grandmother of Love Parry of Penarth, d.1750; in the porch (g) two slate charity inscriptions, one of Evan Griffith donating £100, and the other from Mrs Jones of Ddol, and (h) £100 from Hendre, at 5%, on land yield, dated 1847.