" The well sits on the western side of a road in the townland of Johnswell, opposite a Catholic church, on the eastern slopes of a small stream valley. Its Irish name, Achadh, simply means "the Field," which gives some sense of how thoroughly embedded the site once was in the ordinary landscape of the parish.

The pattern, or patron day festival, fell on the 24th of June each year and drew crowds described as numbering in the thousands, arriving from counties well beyond Kilkenny. A turus, the Irish word for a pilgrimage circuit made around a sacred site, was performed here and was believed to offer protection against all manner of illness. The sole exceptions recorded were love and jealousy, which the well apparently declined to treat. By 1761, the festivities had attracted enough disorder that Dr Burke, Bishop of Ossory, felt compelled to intervene to restore law and order during the gathering. The situation continued to deteriorate over the following decades, and eventually Dr Marum, a later bishop, suppressed the pattern altogether. Writing in 1905, historian Carrigan noted that the turus itself persisted long after the formal festival had been banned, and had not entirely ceased even at the time of his writing. Works were carried out on the well structure in 1897, and what remains today is a well chamber set at the eastern end of two rectangular forecourts. The lower, more westerly of these, roughly 3.5 metres by 10 metres, is prone to flooding; the inner forecourt tapers as it approaches the well chamber itself.