This square tower house, built on a natural platform of rock roughly 40 metres across and 6 metres high, presents an impressive sight with its well-preserved walls. Historical records from the 1840s describe the structure as measuring about 24 feet wide externally, whilst the Ordnance Survey Letters provide more precise internal dimensions of nineteen feet eight inches by fourteen and a half feet. The castle walls, remarkably intact, are about six and a half feet thick; a testament to medieval defensive architecture.

The five-storey tower features an interesting architectural detail on its fourth floor, which is supported by an arched vault underneath. This type of construction was common in Irish tower houses, providing both structural support and creating a defensible stone ceiling for the chamber below. The 1654-56 Civil Survey of Limerick reveals that the Lord of Brittas owned this castle along with a bawn, which was a fortified enclosure typically surrounding such towers. Whilst the castle itself remains clearly visible, the exact location of this defensive bawn wall has been lost to time.

Carrigarreely Castle represents a typical example of the tower houses that dotted the Irish landscape during the late medieval period, serving as both defensive structures and symbols of local authority. These buildings were particularly common in Limerick, where local lords needed fortified residences to protect their holdings and assert their control over the surrounding lands. The survival of Carrigarreely’s walls in such complete condition offers visitors a chance to appreciate the scale and solidity of these remarkable structures that once dominated the Irish countryside.