The name appears on Ordnance Survey maps from 1842 and again in 1916, and the well's particular speciality, the curing of eye ailments, runs through every layer of local memory attached to it. It is also known as St Brigid's Well, though the saint most firmly associated with the place is St Daithlionn, or Dahalin, from whom the glen and the ruined church nearby both take their names.

By 1841, when the Ordnance Survey noted the well in detail, the festival day of St Daithlionn was already forgotten, yet people troubled with sore eyes were still coming on Saturdays to wash in the water. The practice of paying rounds, that is, walking three circuits of the well while reciting the rosary, is recorded as continuing into recent times, particularly on the Saturdays before May Day, Midsummer and Michaelmas. The folklore gathered from several local schools in the mid-twentieth century gives a vivid sense of how seriously the well's sanctity was regarded. One account places the blindings during the Carew and Mountjoy campaigns in Munster, when English soldiers advancing on the convent were struck blind and cured only after the nuns directed them to the well. Another version attributes the miracle directly to St Daithlionn herself, who interceded when a group of would-be attackers approached her small cabin beside the church. A separate tradition holds that a landlord's kinsman named Crosbie, who mockingly threw his dog into the well, was afflicted with madness and died shortly afterwards; a related account from another school says a member of the Crosby family, the Protestant landlords of the area, suffered a permanently dead hand after the same act of contempt. The church ruin nearby, Teampall Daithlionn, had already lost its walls before 1814, according to one account, which gives its dimensions as eighteen feet long, eleven feet broad, and nine feet high. Woven through the folklore is also a guardian trout said to live in the spring, visible only to those about to be cured, and whose removal once caused a pot of water to refuse to boil until both the fish and the water were returned.