Where a typical ringfort, or rath, was raised from soil and sod, a cashel was constructed from the stone that lay ready to hand, and in the limestone-rich landscapes of Clare, that was rarely in short supply. These structures were generally built and occupied between roughly the sixth and twelfth centuries, serving as farmsteads for families of varying social rank, the stone walls enclosing a household, its outbuildings, and whatever livestock needed protecting through the night.

The cashel at Killeen is one of thousands of such monuments scattered across Ireland, though each sits within its own particular patch of ground, shaped by local geology, local history, and the decisions of people whose names are almost never recorded. Clare's Burren region and its surrounding areas are especially dense with dry-stone enclosures, a reflection of the underlying karst landscape where earth is thin and rock is abundant. The specific history of this particular cashel, including who built it, when it was in active use, and what became of it, remains to be properly documented in the public record.