The enclosure measures approximately 140 metres on its longest axis, a scale that places it comfortably among the more substantial early ecclesiastical enclosures in Ireland, even though nothing about it now announces that ambition. At its centre, what was once a church has collapsed into a jumbled spread of large stones and earthen material, the walls reduced to a low bank roughly a metre and a half wide. A gap of about 1.7 metres survives in the southern wall, slightly west of centre, most likely the original doorway.

Ecclesiastical enclosures of this type, in which a circular or oval earthen bank defines a sacred precinct around a church and its associated ground, are understood to represent some of the earliest phases of Christian settlement in Ireland, often predating the stone architecture they eventually came to contain. The outer boundary at Kilcashel is defined by a wide bank, around 3.4 metres across, with an internal height of roughly a metre. At the north-east, a straight section of later field wall interrupts what was probably an original curved line. The church itself, measuring 13 metres east to west and just under 6 metres north to south, sits at the geometric centre of this enclosure, the conventional placement for an oratory or chapel within such a layout. No grave-markers are visible anywhere within the boundary, which is unusual given that early ecclesiastical enclosures frequently served as burial grounds; whether this reflects later clearance, a different function for this site, or simply the passage of time is unclear. A further possible enclosure lies immediately to the east, hinting that whatever community occupied this hilltop may have organised its space across more than one defined area.