What remains at Knockaunnagat is just enough to read the intention of the original structure, but little more: a ghostly oval outline in the grass, its banks softened to scarps, its ditch only partially legible, and a short stretch of dry stone wall trailing off to the south-west as though mid-sentence.

Ringforts, also known as raths, were the dominant form of enclosed farmstead in early medieval Ireland, typically dating from around the sixth to the twelfth centuries. They were built to protect a household, its livestock, and its stores, defined by one or more earthen banks with a ditch, or fosse, between them. The example at Knockaunnagat is a bivallate type, meaning it once had two concentric banks with an intervening fosse, a form generally associated with higher-status occupants. The fort is oval in plan, measuring roughly fifty metres on its north-south axis and thirty-two and a half metres east to west. Of its inner bank, only the north-eastern arc retains any stone facing; the rest has collapsed or eroded into a simple slope. The outer bank and fosse survive in the northern half of the circuit, running from the north-west around through north to north-east, but elsewhere the ground offers little trace. A dry stone wall some sixteen metres long extends from the monument at the south-west and may represent what was once an annexe, a small enclosure attached to the main fort, sometimes used to shelter animals or store goods.

The hillock site itself is characteristic of ringfort placement across the west of Ireland: not dramatically elevated, but positioned just high enough to command a view of the surrounding landscape, with bogland stretching away to the north. The structural remains are sparse, and a casual eye might pass the site without registering it as anything more than an uneven field. The surviving stone-faced arc at the north-east and the low depression of the fosse to the north are the clearest indicators of what once stood here.