What remains today is merely a fragment of the eastern wall, stretching four metres and rising to about three metres in height on its exterior face. The wall, though largely stripped of its original stone facing, still hints at a base batter; a defensive architectural feature common in tower houses of the period. At the northern end, a short section of wall extends westward, marking what appears to have been the northeast corner of a rectangular structure that once measured approximately seven to eight metres east to west and five metres north to south.

Historical maps tell the story of the castle’s gradual decline. The 1838 Ordnance Survey shows it as ‘Knockaunakill Castle’, depicting a square building with field boundaries abutting its north and south sides. By 1920, only the northern portion of the castle remained standing, much as we see it today. The discovery of a punch-dressed stone fragment, likely from a centred door arch, suggests this was probably a 15th-century tower house; one of hundreds built across Ireland during the late medieval period when local lords sought defensible residences to protect their families and assert their territorial claims.

The castle wasn’t an isolated stronghold but part of a larger defensive complex. The knoll’s topography provided natural defences, with steep drops of three to four metres on the northeast side. To the west and northwest, a gentler slope leads to a level terrace enclosed by wall footings, indicating the presence of a bawn; a fortified enclosure that would have protected livestock and provided an outer line of defence. The castle occupied the southeast corner of this enclosure, a typical arrangement for such fortifications. About 350 metres to the north-northwest lies a rath, an earlier ringfort that speaks to the site’s long history of settlement, suggesting this limestone knoll has been valued for its defensive position for centuries before the castle’s construction.