The building has lost both its gables and most of its south wall, yet the ruin is surrounded by a landscape so closely associated with St. Patrick that it clusters several distinct monuments within a few hundred metres of one another: a well to the south-west, and a feature known as Patrick's Seat a short walk to the east, the latter being the remains of a small prehistoric stone cist that tradition has long claimed for the saint. The hill itself had a medieval name too, recorded as 'Knocklaboskor', and the church appears on Jobson's 1589 Map of Munster, confirming it was already a recognised landmark by the late sixteenth century.

The documentary record for the site stretches back to 1336, when the Black Book of Limerick listed it under the curious name 'Desert Alysbokan'. By 1419 it appeared in church taxation records more straightforwardly as 'ecclesia St. Patricii de montan', the church of St Patrick of the mountain. The coarbship, a hereditary ecclesiastical office involving the custody of a saint's legacy and associated lands, was held by the O'Nea family, later anglicised as Neville. That connection had a strange afterlife: a relic called 'Mias Phadruig' was at some point pledged to a Roche of Limerick by one Mary Neville, described as its hereditary keeper and known locally as 'Mary of the dish'. In 1587, Queen Elizabeth granted the church and its lands to William Trenchard under the Munster Plantation, to be held under the name Mount Trenchard. The following year, Shane O'Nea of Knockpatrick disputed the grant through state channels, arguing that the inquisition at Kilmallock had wrongly disturbed his possession, though he acknowledged he could not assert title against the Crown. The architectural historian T. J. Westropp, writing in the early twentieth century, noted that the upper sections of the surviving walls, including corbels with inverted-pyramid profiles and a projecting cornice course, appear to date from a fifteenth-century rebuilding.

When John O'Donovan recorded the church for the Ordnance Survey in the 1830s, both long walls were still standing to a height of around 3.65 metres; by 1840 the structure had deteriorated to something close to what survives today. The north wall, at 16.7 metres, is the more substantial of the two, and contains a narrow pointed-arch doorway near its west end and a round-arched opening near its east end, the latter apparently rebuilt in recent decades. The south wall, now only 6.8 metres long, retains a plain corbel with a socket hole above it. Both walls have been re-pointed in a manner that archaeologists have described as crude, and concrete has been used in places, most visibly around a low abutment near the east end. A ringfort is visible to the north of the graveyard. The graveyard itself remains in use, and headstones from as far back as 1777 and 1798 are recorded; visitors should expect a working burial ground rather than a purely archaeological site.