This National Monument comprises a formidable tower house joined to a sixteenth or seventeenth century stone house, with a small wing between them that likely housed kitchens and servants' quarters. The complex once formed part of a substantial 200-acre estate that, according to the Civil Survey of 1654-6, belonged to Lawrence Dowdall and included not just the castle and stone house, but also a water mill, tuck mill, two fishing weirs, a church and two quarries.

The tower house itself is a compact yet sophisticated defensive structure, measuring roughly 10 by 7 metres with three storeys, an attic, and projecting rectangular corner towers. Its design reveals careful attention to both defence and comfort; a newel staircase spirals up through the north tower, connecting barrel-vaulted chambers, living quarters with fireplaces, and even garderobes for sanitation. The ground floor features a barrel vault with no evidence of a loft floor above it, whilst upper levels contain enlarged windows with built-in seats and various chambers tucked into the corner towers. Particularly clever defensive features include a murder hole commanding the entrance and multiple look-out posts accessed by external stairs, though later additions like gables built over the wall-walks suggest the building evolved beyond its purely military origins.

The castle's dramatic end came in 1690, when tradition holds that Sir Launcelot Dowdall burnt it himself upon hearing news of the Battle of the Boyne's outcome, preferring to destroy his home rather than see it fall to his enemies. Though another account from the 1740s attributes the burning to the Maguire family attempting to deny Cromwell its use, the Dowdall story has endured in local memory. Today, the ruins stand as National Monument No. 287 in state ownership, with the medieval parish church of Athlumney visible just 80 metres away and an ancient motte 140 metres to the southwest, creating a remarkable concentration of historical structures that tell the story of this corner of County Meath across centuries.