At its centre, an ancient enclosure marks one of the more quietly compelling corners of the Irish west, a walled boundary whose age and original purpose remain subjects of scholarly interest. Stone enclosures of this kind, sometimes associated with early Christian monastic settlements or pre-Christian ceremonial use, are a recurring feature of Ireland's Atlantic islands, where communities built in drystone what the mainland might have achieved in earthwork or timber.

Caher Island, whose name derives from the Irish "cathair", meaning a stone fort or enclosure, has long been associated with early Christian activity, and is traditionally linked to pilgrimage routes connecting the island to Croagh Patrick on the nearby mainland. The island contains the remains of an oratory, cross slabs, and leachtanna, the low rectangular cairns that serve as stations along a pilgrimage circuit. The enclosure itself forms part of this wider complex of early medieval remains, the kind of concentrated sacred landscape that surviving island sites occasionally preserve simply because later development never came to disturb them.