It is easy to overlook, and that is part of what makes it worth noticing. Holy wells are among the oldest categories of sacred site in Ireland, places where pre-Christian veneration of water sources was gradually absorbed into Christian practice, with local patron saints replacing older associations and patterns, the traditional rounds of prayer performed at such sites, continuing for centuries.

This particular well at Killaan sits approximately 140 metres to the north-east of the associated church, itself a recorded monument. The well's basin is D-shaped, measuring just under a metre on its north-south axis and a little over half a metre east-west, contained within a drystone surround open to the south-west. Drystone construction, in which stones are stacked without mortar, is the same technique used in many ancient field walls and enclosures across the west of Ireland, and its presence here speaks to a long tradition of modest, local craft. The iron railing above it is clearly a later addition, a small gesture of protection that sits a little incongruously over something so old and unassuming.