The monument, designated as National Monument No. 263, was constructed in 1199 by the Anglo-Norman lord Richard de Tuit as a strategic frontier castle on the northwest border of the lordship of Meath. Its primary purpose was to suppress the O'Reilly clan of southern Breffny, though it would later serve as temporary lodgings for King John himself during his 1210 campaign against the rebellious Hugh de Lacy.

The fortress consists of a substantial subcircular mound rising between 9 and 11 metres high, with a base measuring approximately 50 metres from east to west and 40 metres from north to south. A large D-shaped bailey, stretching 150 metres in length, adjoins the motte without any separating fosse. The summit, which sits about 4 metres above the bailey level, now hosts an Ordnance Survey trigonometrical station and a statue of St Patrick erected in 1932. Early 20th century records mention foundations of a shell wall around the top and a small round tower at the centre, though these features are no longer visible. The defensive works include a formidable rock-cut fosse, 10.5 metres wide and 3.5 metres deep, which encircles much of the motte's base, accompanied by an external bank rising nearly 3 metres high.

Built within an earlier hillfort, this site likely served multiple functions throughout its long history. Archaeological evidence suggests it was probably the inauguration site for the O'Farrell (Bán) chieftains, adding a layer of Gaelic significance to what began as an Anglo-Norman stronghold. The SE face of the motte contains fragmentary remains of a later castle, whilst a medieval church and graveyard lie about 100 metres to the north. Unfortunately, some historical fabric was lost in 1925 when a grotto was built into the north side of the monument using explosives to remove stone; a reminder that our relationship with these ancient sites hasn't always been preservationist in nature.