The monument comprises a high-status Early Historic fort and associated carvings, situated on an isolated rocky massif above the boggy flats of Moine Mhor, adjacent to the River Add.
The natural stepped topography of the massif has been utilised to create a number of terraced enclosures. Approached from a monumental rock cleft in the the SE, the lower terraces are the largest; there is a well at their N end, several rectangular foundations and a small cell in the W angle of the wall. To the E, beyond this main stone wall, is a line of boulders filling gaps between the rocky ridges.
To the E of the summit is an enclosure (22m by 11m) which includes within it a rock-cut basin, an ogam inscription, a boar carving and a sunken footprint (likely to be associated with inauguration rites). The enclosure on the summit, which in its latest phase is pear-shaped (30m by 13m), is pre-dated by what may be the earliest phase of construction of the fort.
There is no evidence for fort activity pre-dating the first millennium AD. Finds from the site are numerous, particularly the evidence for fine metalworking: there are also suggestions that some of the inhabitants were literate and/or Christian. Imported pottery from Gaul and Germanic glass vessels have also been identified. Probable cupmarkings of prehistoric date have been recognised at various points outside the fort on the S and E; there is also a ruinous building of more recent date on level ground 20m to the S of the fort.
The area to be scheduled is irregular on plan and measures up to 280m from WSW to ENE by up to 210m, to include the fort, carvings and an area around in which associated remains may survive, as marked in red on the attached map extract.