This impressive defensive structure, marked on the 1837 Ordnance Survey map, consists of a rectangular raised platform measuring 23 metres northeast to southwest and 17 metres northwest to southeast, with distinctly rounded corners. The site's defences are remarkably well preserved, featuring three concentric rings of earthen banks and ditches, though the outermost defences are missing on the southern side. A causewayed entrance gap breaks through these formidable barriers at the northeast corner, providing the original access point to this medieval stronghold.

Beyond the main enclosure to the northeast lies what appears to be a bailey or annexe; a secondary raised area measuring 37 by 22 metres that may have served as additional living or working space for the castle's inhabitants. This outer ward retains traces of an earthen bank along its southwestern edge and a shallow external ditch, though time has worn these features down considerably. The interior of this annexe slopes gradually from south to north, and careful observation reveals the faint traces of cultivation ridges running northeast to southwest, suggesting the space was later repurposed for agriculture once its defensive role had ended.

The strategic positioning of Castlekid becomes clear when considering its neighbours: a church and graveyard lie 600 metres to the southwest, whilst another motte castle stands 650 metres to the west, creating a network of medieval sites across this part of Westmeath. Aerial photographs from 2011 have revealed additional features surrounding the castle, including what may be remnants of an associated field system or drainage ditches to the north and east, hinting at the broader medieval landscape that once supported this fortification.