What survives today is only the southern half of what was once a substantial tower house, originally measuring approximately 10 by 9 metres. The main structure, built with walls over a metre thick and reaching heights of around 15 metres, comprised three storeys in its central block, whilst a staircase section extended to five levels. Though an 1840 survey suggested the castle wasn't particularly ancient, its core likely dates to the late medieval period, with significant modifications occurring throughout its history.

The castle underwent considerable expansion during the early 17th century, between 1600 and 1640, when a four storey extension was added to the south. This addition, now supported by a sloping buttress at its southwest corner, featured hood-moulded windows that have since been blocked up, along with its original entrance. A further eastern extension, now largely vanished, once housed a wide staircase that connected to where a modern house currently stands. These modifications reflect the changing needs and fortunes of its various inhabitants over the centuries.

The Civil Survey of 1654-56 provides a glimpse into the castle's heyday, recording that in 1641 John Fox of Ballyvenoge possessed not just a 'good castle' but also a bawn (fortified enclosure), an orchard, and several houses of reasonable quality. Following the Cromwellian conquest, ownership passed to Captain Ormsby by 1660, and subsequently to the Gubbins family. The castle's strategic importance is evident from its appearance on Down Survey maps of both Coshma Barony and Dromin parish, where it's clearly marked as a significant structure. Today, parts of the old castle have been incorporated into more recent buildings, with Mr. Coll's dwelling house notably integrating portions of the medieval structure, ensuring that this piece of Limerick's architectural heritage continues to serve a practical purpose whilst preserving its historical fabric.