What remains today are the wall footings of a rectangular building, measuring approximately 9.6 metres north to south and 14.2 metres east to west, with walls nearly a metre thick. The structure sits within the eastern section of a D-shaped enclosure, commonly known as a bawn, which would have provided additional defence for the castle and its inhabitants.

The bawn itself tells an intriguing story of defensive architecture, defined by an earthen bank that has weathered into a scarp on the western and southern sides, whilst a deep, wide outer fosse, now filled in from north to east, once provided formidable protection. A causeway entrance at the southwest corner allowed controlled access to the interior. The relationship between the castle and its enclosure raises fascinating questions; the D-shaped earthwork may predate the castle itself, perhaps representing an earlier fortification that was later repurposed as the castle’s bawn, or it might have been constructed specifically as part of Faheeran Castle’s original defensive scheme.

Adding to the site’s complexity, a series of low linear earthworks southwest of the castle form an irregular pattern that archaeologists interpret in two possible ways: they might represent the remains of a medieval settlement associated with the castle, or alternatively, they could be the result of later agricultural land reclamation efforts. These ambiguities make Faheeran Castle a particularly interesting site for understanding how defensive structures evolved and were adapted over time in medieval Ireland.