At the northern foot of St Patrick's Hill in County Kildare, a small holy well sits submerged beneath its own floodwater. Beneath the surface, if conditions allow a clear view, the outlines of a roughly two-metre-square enclosure are still visible, defined by ivy-covered drystone walls and open to the south. A large flat stone along the southern edge may once have formed part of a roof structure, suggesting the well was at some point deliberately enclosed, a common treatment for sites considered sacred or curative.

The well does not appear on the first edition Ordnance Survey six-inch map of 1838, yet it was clearly well-known in the area long before that survey was made. Writing in the mid-1870s, Shearman noted that the site was still being visited by pilgrims who tied votive offerings of rags to an ancient thorn tree overhanging the water. This practice, sometimes called rag-hanging or clootie offerings, is one of the oldest and most widespread forms of devotion associated with holy wells in Ireland, the rags thought to carry illness away from the person who left them. By the late twentieth century, the well was recorded as having a particular association with cures for sore eyes and as a place of pilgrimage on St Patrick's Day. The thorn tree noted by Shearman is separately recorded as a heritage feature in its own right.

The well lies in a small thicket on the southern roadside at the base of the hill, though the persistent flooding, possibly caused by the spring itself, makes direct access to the structure difficult. The submerged stonework is the clearest indication of what was once here, and what may still be here, underneath.