The 1838 Ordnance Survey Letters note it plainly: sessions were held, a gallows stood, and this was where Tirawley assembled. That combination, judicial, commercial, and social functions folded into a single earthwork on an unremarkable hill, gives Rathnabart a quietly unsettling character that the rough pasture surrounding it does little to dispel.

The enclosure itself is broadly oval, measuring roughly 108 metres on its longer axis, and is defined by a substantial stony bank that still stands up to two metres on its outer face at the north-east, though it has degraded and broken in places elsewhere. A rath, in Irish terms, is typically an enclosed farmstead of the early medieval period, defined by one or more earthen or stone banks, but Rathnabart's social history suggests a more public function, at least in later centuries. The name appears on both the 1837 and 1929 Ordnance Survey six-inch maps. An outer bank follows the curve of the enclosure at some distance, separated from the inner bank by a broad flat-based gap marked by rush growth, though whether this outer ring is original or simply the result of later field boundaries absorbing the site is uncertain; it does not appear on the 1838 map and by 1929 it seems to have been incorporated into an ordinary field system. Lough Dalla, now drained and grassed over, is visible to the north-west from the top of the bank, and the profiles of Nephin and the Nephin Beg range rise to the south-west.

The interior is level but damp, with a wet pool of around ten metres across in the north-west quadrant and a low field bank cutting across it roughly east to west. A laneway that once skirted the enclosure, visible on the 1837 map, appears to survive in fragments at the south-east. The most likely original entrance was on the east side, where the hill slopes gently enough to make approach straightforward, though the ground inside would have been soft underfoot then as it is now.