A cashel is a ringfort built from stone rather than earth and timber, the walls raised without mortar in the dry-stone tradition that suited the rocky terrain of the west of Ireland. Where an earthen ringfort, or rath, was thrown up from banked soil and ditch, a cashel relied on the sheer mass and interlocking weight of local stone, and in parts of Clare the geology makes this the natural choice. These enclosures date broadly to the early medieval period, roughly the fifth to the twelfth centuries, and served as the fortified homesteads of farmers and petty lords rather than military strongholds in any grand sense.

The specific history of this particular cashel at Rinneen remains difficult to trace in detail. What can be said is that the townland sits in a part of Clare where early medieval settlement was dense, the land divided among countless small farming households each occupying its own defended enclosure. The stone walls of a cashel like this one would have enclosed a dwelling, perhaps outbuildings, and enough space to bring in livestock at night against wolves and raiders. Many such structures survive across the Burren and its fringes in varying states of preservation, some reduced to a scatter of tumbled stone, others still carrying several courses of walling above the ground.