This rectangular earthwork, measuring approximately 36 metres east to west and 29 metres north to south, represents a fascinating piece of medieval Irish architecture that bridges the gap between native Gaelic building traditions and Anglo-Norman defensive innovations. The site gained particular fame through two 14th-century Gaelic poems that provide remarkably detailed descriptions of its defences, fortified entrance, great hall, and various other buildings within its walls. The Annals of the Four Masters refer to it as the ‘square fort’ of Cloonfree in 1306, marking it as a significant seat of power during a turbulent period in Irish history.

Today, the site presents itself as a scrub-covered rectangular enclosure defined by substantial earthen banks and moats that still retain much of their original impressive scale. The flat-topped inner banks rise between 1.8 and 2.3 metres on their external faces, with bases spreading 4 to 5 metres wide, whilst flat-bottomed moats, measuring 6 to 8 metres across at their tops, provide an additional defensive barrier. Outer banks once completed the fortification system, though the eastern section has since been removed. The entrance, positioned towards the western end of the southern side, consists of carefully aligned gaps in both the inner and outer banks, with traces of stone facing still visible near the southeast angle; evidence of the site’s once-sophisticated construction.

What makes Cloonfree particularly significant is how it demonstrates the adaptation of Gaelic lordly residences in response to changing military and social conditions of the late medieval period. The poems that describe the site, studied by scholars Quiggin in 1913 and McKenna in 1923, offer an extraordinarily rare glimpse into how such fortifications functioned as both defensive structures and symbols of lordly authority. The O’Conors, as one of Connacht’s most powerful Gaelic families, created at Cloonfree a residence that combined traditional Irish hall-house architecture with the defensive earthworks more commonly associated with Anglo-Norman mottes, resulting in a unique hybrid fortification that speaks to the complex cultural exchanges of medieval Ireland.