Built around 1460 to 1480 by the noble Fitzgerald family, specifically the Knight of Glin, this once magnificent fortress originally comprised a five storey tower measuring roughly 12 metres by 9 metres, enclosed within two defensive walls, or bawns. The inner courtyard formed a 17 metre square, whilst the outer defences stretched considerably further, creating a formidable stronghold that dominated the local landscape. Early observers marvelled at its sophisticated construction, noting the polished square quoins, carved stone windows, and vaulted ceilings on the second and fourth floors.

The castle’s turbulent history reflects centuries of Irish conflict and changing ownership. Church records from 1201 show the lands were held by the Bishop of Limerick, but by 1302 the area had been devastated by war. Throughout the following centuries, Cappagh changed hands repeatedly; it was granted to various English administrators in the late 1500s after local chieftain Walter Boorke was attainted, lay waste and unpeopled for years, and eventually came under siege during the 1642 Confederate Wars when it was blockaded and forced to surrender. By 1655, observers noted it stood ruined within its great bawn, a shadow of its former glory. Local tradition preserves a dramatic tale of sibling rivalry, claiming that when one Fitzgerald brother demanded the return of Cappagh Castle from another, the spurned brother retaliated by blowing up the first brother’s castle at Ballyglehane the day before he was due to surrender it.

Today, visitors can still appreciate the castle’s impressive engineering and strategic position. The remaining north wall showcases the quality of medieval Irish masonry, with one particularly fine window surviving at the fifth storey level. The defensive layout remains visible; the western walls were cleverly built atop natural rock faces for added protection, whilst a round turret guarded the northeast corner and gates controlled access through the southeast. Archaeological surveys have identified the locations of the spiral staircase in the southeast corner, mural chambers above the eastern entrance, and a fireplace in the third storey’s north wall, all testament to what the Ordnance Survey once called “a truly magnificent structure” that “reflects honor on the noble family of Desmond.”