The name translates from the Irish as "well of the hillside", a plain enough description, yet the site it labels carries layers that stretch well beyond a simple water source.

When the Ordnance Survey mapped the area in 1842, Toberlackan sat within a circular enclosure, the kind of bounded space that in an Irish context often signals an early ecclesiastical or ritual function. By the time surveyors returned in 1916, that enclosure had largely disappeared from the record, leaving the well without its original frame. What remained, and remains still, is the complex of underground chambers lying immediately behind the well. Souterrains, as these stone-lined subterranean passages and chambers are known, were built throughout early medieval Ireland for storage and refuge, though their precise functions varied by site. Here, however, the suggestion is older and stranger: the chambers may originally have served as some form of ancient burial place, a site later absorbed into Christian practice and associated with a figure known as St Lacken. The pattern is a familiar one in Irish religious geography, where pre-Christian sacred places were quietly re-dedicated rather than abandoned, the new faith settling itself into the landscape rather than clearing it.