Its interior dimensions, roughly 7.5 metres north to south and 4.5 metres east to west, suggest a modest but purposeful structure, yet beyond its outline and position within the enclosure, the record is largely silent on when it was built or by whom.

A cashel is a dry-stone ringfort, a type of enclosed settlement common across Ireland from the early medieval period onward, though many continued in use or were adapted across later centuries. The Ballyganner example contains not one but two house sites, and their arrangement is telling. A second structure, recorded on the 1920 Ordnance Survey six-inch map under the evocative label "Ancient Dwelling", was built directly against the cashel's eastern wall, as though seeking shelter or support from the older stonework. That a mapmaker in 1920 thought fit to name it separately, and to call it ancient, implies the ruin was already striking enough to warrant special attention at a time when such features were only beginning to be systematically recorded. The two structures, one sheltering in the south-west corner, the other leaning against the east wall, suggest that the interior of this cashel was once organised domestic space, with different areas given over to different purposes or perhaps different periods of occupation.