The bank, which survives most visibly along the south-east to south-west arc, has been quietly absorbed into the local field fence system over the centuries, its height uneven, likely because material was deposited onto its surface at some point after it ceased to function as a boundary in any active sense. The outer fosse, a shallow defensive ditch originally cut to about a metre deep, is now heavily overgrown, and on the north side of the enclosure the original earthworks have flattened to little more than a low rise with a slight depression beside it.

This is a rath, the most common type of early medieval settlement monument in Ireland. Raths were typically enclosed farmsteads, built and occupied roughly between the fifth and twelfth centuries, where an earthen bank and fosse defined a protected space for a family, their livestock, and their domestic buildings. Tens of thousands once existed across the island, though many have been ploughed out or built over. What makes Knockbrack quietly notable is the souterrain in its south-east quadrant. Souterrains were underground stone-lined passages or chambers, dug beneath or beside a ringfort's interior, and used variously for storage, refuge, or as a cool environment for dairy produce. They represent a significant investment of effort, and their presence usually suggests a settlement of some substance. The interior of this enclosure slopes downward to the south, meaning the souterrain's entrance would have opened into a portion of the site that already had natural drainage running away from it, a practical detail that says something about whoever chose this location and planned its use.