Among its monuments is a leacht, a type of low commemorative or devotional cairn, typically a rectangular or square mound of stones, sometimes associated with a saint or used as a station during penitential rounds. These modest structures are easily overlooked, lacking the drama of a round tower or carved cross, but they carry a particular weight in the landscape of early Irish Christianity.

Caher Island has long been connected with St Patrick, and the site as a whole is understood to be an early medieval religious enclosure. The island's very name, from the Irish cathair meaning a stone fort or enclosure, hints at the layered uses of such places, where pre-Christian and early Christian monuments sometimes occupy the same ground. Pilgrimage to the island was traditionally associated with the pattern day on the last Sunday of July, part of the wider Croagh Patrick pilgrimage circuit that drew devotees through this stretch of the Mayo coastline for centuries.