c. chapel", which is to say, a Roman Catholic chapel already reduced to memory at the time the surveyors came through. What remains on the ground today is an oval earthen platform, roughly fifty metres across and a metre in height, with a rectangular hollow cut into its eastern end. That hollow is likely all that survives of whatever structure once stood here, and the platform itself, sitting on wasteland behind a house and garden along a trackway at the estuary's edge, is easy to overlook entirely.

Local tradition reaches back considerably further than the nineteenth century map. According to accounts recorded by Ó Danachair in 1958 and Healy in 1975, the site is associated with St. Mochuda, an early Irish monastic figure, who is said to have built a church close to his holy well. A holy well, in the Irish tradition, is a spring or water source with sacred associations, often linked to a founding saint and used for patterns, prayer, and pilgrimage across many centuries. That well is said to lie to the south of the platform. Whether the earthwork represents the remains of the early medieval church, a later chapel built on the same hallowed ground, or simply accumulated debris around a long-used sacred site is not recorded in the sources.

The site is on wasteland adjoining a trackway that runs along the Rogerstown estuary, between Rush and Donabate on the north Dublin coast. The estuary itself is a recognised wetland of some ecological significance, and the track along its edge is walkable, though the chapel platform is described as overgrown. Visitors should expect rough ground rather than any kind of managed heritage presentation. The well to the south is worth looking for separately, and given the density of vegetation the earthwork is likely easier to read in winter, when growth dies back and the low platform and its hollow become more legible from ground level.