A cashel is a type of ringfort built from dry-stone walling rather than earthen banks, a construction method that suited the rocky terrain of the west of Ireland and that gives these enclosures a particular durability. Thousands of ringforts were built across Ireland, mostly during the early medieval period, roughly between the fifth and twelfth centuries, and they functioned primarily as enclosed farmsteads, the circular wall protecting a family, their livestock, and their stores. The cashel at Bearnafunshin is one of many that dot County Clare, a county whose limestone geology made stone the most natural building material available.

Beyond its classification and its location, very little about this particular site has been formally documented in accessible public records. The townland name itself is of interest: Bearnafunshin derives from the Irish, and Clare is thick with such placenames that carry traces of older land use, topography, and habitation. The cashel would have been a working enclosure in its time, the centre of a small farming household, its walls serving a practical rather than a ceremonial purpose. Whether much of the original structure survives above ground is not currently known from available sources.