A post-1700 mausoleum was built flush against the southern exterior wall of a medieval church, and in doing so, whoever commissioned it inadvertently sealed off two features that would otherwise still be legible: a small aumbry, a wall cupboard used in liturgical practice to store vessels or the reserved sacrament, measuring just half a metre square, and a single-light window immediately to its west. Both are now blocked. A little further along the same wall, the western splay of another window survives where the opening itself has been broken out. The southern wall is the best-preserved section of the structure, reaching about 2.1 metres at its highest point externally; elsewhere, only the lowest courses of masonry, roughly 0.4 metres high, trace the rectangle of the nave across the northern quadrant of the graveyard.

The church belongs to the medieval parish of Cahervally, a place recorded under a string of variant spellings across several centuries. The antiquary T.J. Westropp, writing in 1904 to 1905, traced the name back to early thirteenth-century sources: Cahirdubaulig in 1201, Kathirdufauli in 1204. John Pincerna granted the church, along with two others, to augment the prebend of Thomas de Kerdiff around 1260, and in 1290 to 1296 a Richard Wodeford pursued a legal claim over it against a Patrick le Myneter. By 1410 the dedication was recorded as St Thomas the Apostle, whose feast falls on 21 December. The Irish scholar John O'Donovan interpreted the place-name as Cathair Uí Bachalla, meaning the fort of the O'Boughils, and the landscape still carries echoes of that older layering: the remains of Raheen Castle and its bawn, a walled enclosure associated with a tower house or fortified dwelling, sit roughly 70 metres to the west-southwest, with traces of an earlier fort on the higher ground close by. When Westropp measured the church walls around 1840 in his account of earlier surveys, only portions of the ends and the north side were still standing to any height.

The site occupies elevated ground with open views across the surrounding countryside, which makes it relatively straightforward to locate even before you find any formal access point. The possible original doorway is now visible only as a gap in the low north wall, set slightly off-centre towards the northwest angle. The interior holds several post-1700 memorials. The blocked aumbry and window in the south wall are most clearly read from outside, where the mausoleum structure makes the interference with the earlier fabric plain to see.