Today, only grass-covered wall footings mark where a tower house once stood at the northeast corner of a raised circular enclosure, measuring roughly 36 metres north to south and 33.6 metres east to west. This elevated platform, standing 1.7 metres high, served as the castle’s bawn; a defensive courtyard typical of Irish tower houses. Rock outcroppings that have been quarried into flank the site to the north and south, whilst the medieval ruins of Cahervally Church and its graveyard lie just 50 metres to the east-northeast.

The origins of this circular enclosure remain something of a mystery to archaeologists. It may have started life as an earlier ringfort, or possibly an Anglo-Norman ringwork, which was later adapted when the tower house was built, with a defensive wall constructed along its edge to create the bawn. Alternatively, the entire complex; enclosure, wall and tower house; might have been built as a single project. The grass-covered remnants of the bawn wall that once ran around the enclosure’s perimeter are still visible today, offering tantalising clues to the site’s defensive past.

Historical records provide glimpses of the castle’s long history, with references dating back to 1336 when it appears as Rathendessy in de Rupefort’s Rental. By the late 16th century, various members of the O’Kahisse family held the site, though by 1583 it was already described as an “old very ruinous” castle. The property later passed to the Roche family, with William Roche holding Cahervahilly in 1623. The site gained particular distinction when James II created Dominick Roche, who had served as Mayor of Limerick in 1691, Viscount of Cahiravahalla and restored the family estates to him. This same Roche lineage would later produce Sir Boyle Roche, remembered for his colourful contributions to parliamentary oratory.