Built in a mixture of Gothic Early English and Decorated styles, long-wall entry type. 

St Llywel’s Church is first mentioned in 1254 and is situated to the east of the River Usk in the village of Llanllowell, Monmouthshire. A curvilinear churchyard has on its southern boundary a stream whilst to the west end is a slight bank that cuts across, and may have been an old boundary. The church is usually claimed as Norman on the basis of the slit windows in the north and west walls, and the semi-circular rear arch to the main door, although the doorway in its present form is certainly later. However the dedication is Celtic. The nave and chancel is made of squared rock-faced blocks of sandstone laid in snecked courses on exterior face, with an interior of roughly coursed rubble. The church and graveyard appear on the 1845 Tithe map as well as OS historical maps.

Some restoration of the church took place in 1871-72  which included a new north and east walls under architect John Prichard of Llandaff. Restoration works also sought to match the doorway to the early slit windows; a square-headed outer doorway and a semi-circular inner face to the rear arch also suggests this. The form of the doorway and the method of working the stone bears similarity with the church at Llandenny, and it is probable that they were closely contemporary. The church’s east window (chancel) is a triplet of cusped lancets that has been restored. The other window in the chancel on the south wall is of 15th/16th-century type, nearly identical with the south window of the nave except in the stone used. The porch is of separate construction from the nave; its door head having been renewed and the mouldings indicate that it must have been after 1300. The bellcote, the rebuilding or refacing of the north wall and two larger windows set in it all date to a Victorian restoration. The font may be medieval but otherwise all the internal fittings are believed to be Victorian or later.

A listed building application was made in 2024 to convert the church to a two-bedroom dwelling.

P.C.Tomlins, RCAHMW, 12.12.2002. Updated by M. Powel, RCAHMW. March 2024.

Sources: 'Gwent Historic Churches Survey. Churches in the Archdeaconry of Monmouth, Deanery of Raglan & Usk', Cadw Historic Churches Project, January 1997, produced by E.M. Evans; 'Llanllowel and Llanmartin: Brief hand-written notes and references from various sources on St Llywel's Church and St Martin's and Pencoed Castle', BWGG - Buildings of Wales Glamorgan and Gwent Publications Archive.