In a field of level pasture in County Kildare, a small hollow worn into a natural rock outcrop has long been credited with the power to cure warts. The hollow is modest by any measure, roughly forty centimetres across and a quarter of a metre deep, barely large enough to catch rainwater, yet it has its own local name, the Wart Well, and its own ritual logic that sets it apart from the more elaborate holy wells found elsewhere in Ireland.

The tradition holds that the depression was made by the hoof of St Brigid's horse, which struck the rock and left this lasting impression. Brigid, the fifth-century abbess of Kildare whose cult spread across the island and far beyond, is a frequent presence in the folklore of this county in particular, and sites associated with her often carry a mixture of the miraculous and the domestic. The cure the well offers is a structured one. A visitor must come three times in total; on the first visit a pin is left at the hollow, and by the third visit, according to tradition recorded by Jackson in 1979 to 1980, both the pins and the warts will have gone. The well sits about a hundred metres to the north-west of a ruined medieval church, which places it within a landscape already layered with older religious significance.