The lands here, also known as Kilcowanmore, were first recorded in 1247 when Adam Keating held them as half a knight’s fee from William de Valence, a powerful Anglo-Norman lord. The Keating family maintained their grip on this territory for over three centuries, establishing themselves as one of the enduring Hiberno-Norman families of the region.

By the time of the Civil Survey in the 1650s, the local power dynamics had shifted somewhat. Luke Keating still held 500 acres in nearby Ballybrittas in 1641, but the Ballybrennan lands had passed to Thomas Fitz Harris, who controlled an impressive thousand acres spanning Ballybrennan, Carrigunane and Tomfarney townlands. Despite the strategic importance of these holdings, no documentary evidence survives to describe the castle that once stood here, leaving historians to piece together its existence from maps and field evidence.

Today, visitors to the site will find little to suggest its former importance. The Ordnance Survey maps of 1839 and 1925 mark it simply as ‘Castle (Site of)’, and all that remains visible is a circular mound approximately 25 metres in diameter and barely a metre high. This unassuming earthwork likely conceals the castle’s foundations, though modern land reclamation has piled spoil around it, further obscuring whatever medieval masonry lies beneath. It stands as a subtle reminder of how the Irish landscape holds countless such forgotten strongholds, their stories preserved only in old deeds and survey records.