In 1930, a local boy discovered one of the finest gold gorgets ever found in Ireland wedged in a rock crevice nearby, a lunula-style collar dating to the Late Bronze Age and now among the treasures of the National Museum. That the valley also contains a cashel, a type of stone-walled ringfort built without mortar from the Burren's abundant limestone, is the quieter footnote that tends to get overlooked in the shadow of that gleaming find.

Cashels are the stone equivalent of the more familiar earthen ringfort, and the Burren produced them in considerable numbers precisely because stone was easier to come by than soil deep enough to build ramparts. They functioned primarily as enclosed farmsteads during the early medieval period, roughly from the fifth to the twelfth centuries, though some examples have earlier origins. The Gleninsheen cashel sits within a landscape that has been in almost continuous use since the Neolithic, its limestone pavements, megalithic tombs, and field systems forming one of the most legible ancient landscapes in western Europe. The proximity of the cashel to the findspot of the gorget is, as far as is known, coincidental, but it does place two very different periods of prehistoric and early historic activity within the same small valley.

Gleninsheen lies within the Burren National Park, and the area around it is accessible on foot from the Caherconnell and Poulnabrone directions. The limestone underfoot makes for slow going in wet weather, and the rock itself can be deceptive, flat slabs giving way without warning to deep grikes, the narrow fissures that characterise Burren pavement. The cashel itself is modest and should not be approached expecting a well-preserved monument; like many such structures in the region, its walls have been robbed over centuries for field boundaries and farm buildings, leaving a footprint more than a standing structure.