The circular platform, measuring 20 to 25 metres across, tells the story of a medieval fortification that once commanded views across the lake and countryside. Today, a 20-metre strip of flat, rocky ground separates the castle from the water’s edge, carpeted with ash and hazel trees, though the western side of the mound drops away almost vertically in an eroded cliff face that suggests the lake waters once lapped directly at the castle’s base.

The castle’s defences remain clearly visible in the landscape. A broad fosse, eight metres wide at the top and narrowing to three metres at its base, curves around the northern and southeastern sides of the motte, cutting 1.7 metres deep into the earth. On top of the platform, which measures roughly 14 metres north to south and 11 metres east to west, the remnants of an enclosing wall can still be traced along the northern and eastern edges, surviving as low, sod-covered footings about a metre wide. The most substantial remains belong to a small rectangular building on the southeast side of the platform top, where two walls form an L-shaped corner; the western wall stands seven and a half metres long, still displaying two courses of its original stone facing, whilst the northern wall extends nearly five metres eastward as a grass-covered stony rise.

A narrow causeway extends from the southeastern slope of the platform, bordered by the fosse on one side and faced with stone walling on the other, providing what was likely the main access route to this stronghold. Though the 1838 and 1930 Ordnance Survey maps mark the site as ‘Castle Kelly (in Ruins)’, suggesting a long history of abandonment, the earthworks remain remarkably well-preserved. The gentle pastureland stretching away to the east and southeast contains subtle surface undulations that hint at additional structures, possibly a bailey, though nothing definitive remains. About 300 metres to the east, a rath provides evidence of even earlier settlement in this strategic location overlooking Lough Conn.