A cashel is a type of ringfort built from dry-stone walling rather than earthen banks, and this one still traces a rough circle roughly 42 metres across. The wall itself no longer stands as a coherent structure; instead, it survives as a sprawl of stone, much of it added to over the years as farmers cleared surrounding fields and piled the loose rocks wherever a convenient mound already existed. That process of clearance, repeated across generations, is part of why so many Irish ringforts look ambiguous from a distance, their original form softened and complicated by centuries of agricultural tidying.

Ringforts of this kind were the dominant settlement form in early medieval Ireland, typically serving as enclosed farmsteads for a single family or small kin group, and were built in their thousands across the country between roughly the sixth and tenth centuries. The name Caherhemush carries the Irish word cathair, a common element in place names across Connacht that signals a stone enclosure of this type. The site sits within the wider district covered by a 1994 archaeological survey of Ballinrobe and the areas around Lough Mask and Lough Carra, a region whose landscape holds considerable early medieval and prehistoric remains. At the time of that survey, the northern half of the cashel was already heavily overgrown, and the interior was described as very uneven, the ground broken by collapsed walling and the accumulated debris of a structure slowly returning to the field around it.