On its southern bank, set into a hollow in the ground, lies a circular holy well roughly two metres across, enclosed by a low drystone wall with a single gap on the western side left open for access. The wall is crude rather than decorative, built to demarcate rather than to impress, and the whole arrangement has the quality of a place that has been quietly maintained rather than restored or commemorated.

Holy wells in Ireland were sites of localised veneration, often predating Christianity and absorbed into it, used for patterns, prayer rounds, and the leaving of offerings. The well at Cornacullew carries the usual cluster of associated features that mark such sites as genuinely old. A holy tree stands at its northern edge; these trees, typically hawthorn, ash, or occasionally elder, were bound up with the sanctity of the well itself, their branches hung with rags and tokens by those seeking cures or favours. A few metres to the south-east, a small circular mound of earth and stone once had a wooden cross standing on it, though the cross is gone. Across the stream to the north lies a burial ground, placing the well at the edge of a small sacred landscape in which water, tree, mound, and the dead were all held in close relation to one another.