The original structure, a five-storey tower house built around 1490 by Turlough Donn Ó Briain, King of Thomond, was later joined by a fortified house added to its western side in 1648. Today, only the service wing of the tower remains, constructed from dressed limestone blocks and containing the original stairs and small chambers with narrow lights. The tower’s defensive features are still evident, including pointed doorways with bar-holes, murder-holes, and gun-loops; though curiously, it contained only one fireplace at third-floor level and no garderobes, suggesting a somewhat spartan existence for its early inhabitants.

The castle’s history reads like a chronicle of Ireland’s turbulent centuries. After Turlough Donn’s death, the property passed through various O’Brien hands until 1639, when Conor O’Brien married the formidable Maire Rua and subsequently built the adjoining fortified house. Their son Donough resided here until 1684 before relocating to Dromoland, after which the castle passed through generations of the O’Brien family. By 1773, it had come into the possession of Charles MacDonnell through his marriage to Catherine O’Brien, but the MacDonnells, preferring their residence at Newhall, allowed Leamaneh to fall into disrepair. The castle likely remained inhabited until about 1800, after which it gradually succumbed to the elements.

The architectural details reveal fascinating insights into medieval and early modern Irish life. The ground floor entrance features elaborate defensive mechanisms, including a pointed outer door with a yett recess and a squint opening onto the stairs, whilst the upper floors showcase ogee-headed windows and vaulted chambers with wicker centring. The complex originally included two walled gardens with fish-ponds, multiple gate piers, and a grand gateway that was relocated to Dromoland Castle in 1907. One particularly intriguing detail is that the fireplace from the third floor, dated 1553, was removed in the 19th century and now resides in a tower house at the Old Ground Hotel in Ennis. The road leading south towards Corofin bears the name ‘Sir Donat’s Road’ after Donough O’Brien, who was created a Baronet in 1686. Now designated as National Monument number 448 under State care, Leamaneh Castle remains one of County Clare’s most evocative ruins, its weathered stones bearing witness to five centuries of Irish history.