The building looks, at a glance, like a medieval survivor: limestone masonry, crenellated parapets, a Tudor-style doorway, and pointed arched windows. Look more closely, however, and the picture becomes more complicated. The crenellations are plastered brick, the tall windows in the south wall are brick constructions, and the structure as a whole is a later building into which genuine fragments of medieval architecture have been carefully, or perhaps opportunistically, inserted. It is the kind of place that rewards a second look precisely because it resists an easy reading.

The church measures roughly 8.2 metres east to west and 7.1 metres wide, a modest footprint. Its most accomplished feature is the double-light window in the east gable, with cusped tracery, the decorative stonework of interlocking curved shapes that was characteristic of Gothic ecclesiastical building. That window, along with other medieval fragments worked into the fabric, suggests the builders had access to material from an earlier structure, possibly one dismantled or fallen into ruin nearby. The site is noted in D'Alton's 1838 survey and again in Joyce's 1912 account, though neither source is elaborated upon in the available record. What is clear is that by the nineteenth century the building was already being observed and described, its hybrid character apparently unremarkable to contemporaries in an era when romantic medievalism and architectural salvage were both common impulses.

The church is reached via a tarmacked walkway within St Catherine's Park, which sits along the Liffey north of Leixlip. Visitors should be aware that the interior is heavily overgrown, and a structural survey carried out in 2011 found the building to be in a poor and deteriorating condition, describing it as a clear example of the harm that unchecked vegetation can cause to historic masonry. Access to the interior is not advisable, but the exterior, including the east window and the Tudor doorway on the west face, can be examined from outside. The building is easiest to observe in late autumn or winter, when the surrounding vegetation dies back and the stonework becomes more legible.