What remains at Knocknageeha is essentially a memory pressed into the ground: a roughly circular area, about 36 metres east to west and 32 metres north to south, enclosed by a low rise of earth, with a shallow external fosse, a ditch running around the outside, still faintly traceable to the north, east, and south-west. A second low rise to the north and east hints that there may once have been an outer bank as well, which would have given the original structure a more substantial, double-ringed profile. A rath, as this type of monument is generally known, was typically an enclosed farmstead of the early medieval period, its earthen bank and ditch serving as much to define status and territory as to provide any serious defence. This one survives only as a slight undulation in a pasture field on a gentle west-facing slope.

The 1842 Ordnance Survey six-inch map shows it clearly, drawn as a hachured circular enclosure, so it was still recognisable at that point. By the 1930s, however, two separate researchers were noting its destruction. Bowman, writing in 1934, recorded it as one of three levelled single-ramparted forts on land belonging to a Miss Victoria Allen. A few years later, Broker placed its demolition more precisely, describing it as a fort in a field known as Pairc Cait, levelled during the tenure of someone named Philpott, around 1870. The Irish field name, Pairc Cait, meaning roughly "Kate's field", is the kind of local detail that tends to outlast the monument itself, preserved in conversation long after the earthwork has been ploughed flat. The loss of three forts from a single landholding was not unusual for the period; the clearance of ringforts accelerated considerably during the nineteenth century as agricultural improvement reshaped the Irish landscape.