A cashel is simply a ringfort built from dry-stone walling rather than earthen banks, a distinction that tends to reflect the local availability of stone rather than any difference in purpose or status. These enclosures were the basic unit of rural life in early medieval Ireland, typically housing a single farming family and their animals, and Mayo has no shortage of them scattered across its fields and hillsides.

Beyond its classification and location, the specific history of this particular cashel remains largely undocumented in any publicly accessible form. What can be said with confidence is that ringforts in general date predominantly to the period between the sixth and tenth centuries, though many continued in use or were adapted long after that. The choice of stone construction in this part of Connacht is unsurprising given the geology of the region, where loose field stone has always been more plentiful than the timber or earthwork materials used elsewhere. The townland name Cuillonaghtan itself is of Irish origin, and like many such place names in the west, it likely preserves a reference to an older landscape feature or family association that predates even the monument it now helps to identify.