Beneath them, partly obscured by tumbled stone and overgrowth, there appears to be a hollow, which may indicate an intramural chamber, a small passage or cell built within the thickness of the wall itself, a feature occasionally found in Irish stone ringforts. It is the kind of detail that rewards a close look, and it sits quietly amid a structure that might otherwise be taken at first glance for a simple field boundary.

A cashel is a type of ringfort defined by a dry-stone wall rather than an earthen bank, and the example at Doonmacfelim is a well-preserved one. Its subcircular enclosure measures roughly 21.5 metres north to south and 19.25 metres east to west, and its double-faced wall, wider at the base than at the top, still stands to an external height of up to 1.7 metres in places. The cashel sits on a level limestone outcrop, and from it there are wide views southward over an extensive field system that appears to span multiple periods of use. The site was already being recorded cartographically by the late nineteenth century, appearing on the 1897 Ordnance Survey 25-inch plan and again on the 1920 edition of the six-inch map. What makes the setting particularly unusual is the density of related monuments nearby: another cashel lies around 29 metres to the north-east, a further one approximately 38 metres to the south-west, and an enclosure around 84 metres to the north-east. This is not an isolated farmstead but part of what appears to have been a concentrated cluster of enclosed settlements on the limestone.

The interior of the cashel is heavily overgrown and stony, with several upright slabs still visible among the vegetation. A small rectangular animal shelter, built at some later point against the outer wall face to the north-north-west, is a reminder that the structure has continued to serve practical purposes long after its original function was forgotten. The three large capstones on the wall at the west-south-west are the most immediately striking feature and the likeliest clue, if the hollow beneath them is ever properly examined, to how the wall was originally engineered.