The site is a ringfort, or rath, a type of enclosed farmstead typically dating from the early medieval period, roughly the fifth to twelfth centuries, when such enclosures served as the homesteads of farming families across Ireland. Thousands survive in various states across the country, but most have lost the legibility this one still quietly retains, its shape persisting in the pasture long after the people who built it are forgotten.

The Ordnance Survey's six-inch map of 1840 records it as 'Knockbrack fort', depicting a circular area defined by a scarp, the term for a slope or bank where the ground has been cut away or built up. By the time the more detailed twenty-five-inch edition was published in 1897, surveyors could record it more precisely: an oval measuring roughly 39 metres north to south and 55 metres east to west, enclosed by an earthen bank running from the south-west around to the north, where the bank is reduced elsewhere to a scarp. An outer fosse, that is, a defensive ditch, was recorded along the northern to eastern arc and again at the south, with a gap in the enclosure at the north-north-west. The fort sits in pasture about 20 metres north-west of a watercourse that marks the townland boundary with Tooraleagan, and 50 metres west of the Monaheancree Stream, which here separates Limerick from Cork.

On the ground today the earthworks are not dramatic, but the site shows up more clearly from above. Aerial and satellite imagery taken between 2011 and 2013, including images on Google Earth, reveals an oval cropmark, the outline of the enclosure traced by a ring of trees whose roots follow the line of the buried bank and ditch. Cropmarks of this kind appear most distinctly during dry summers, when grass or crops over disturbed or compacted soil respond differently to stress than the surrounding field. The site is in agricultural land, so access should not be assumed, but the Google Earth orthoimages compiled by Martin Fitzpatrick in 2021 give a useful overhead orientation before any visit is considered.