Historical records show the castle was standing in 1574 under the ownership of Thomas Balve, though its origins likely stretch back earlier. Today, visitors to the site will find several enormous chunks of uncoursed limestone masonry strewn across the top of the motte, some weighing upwards of ten tons. These massive blocks have remained remarkably intact despite the castle’s destruction, bound together by mortar that local tradition claims was mixed with animal blood, sand, and lime; a combination that has proved surprisingly durable over the centuries.

The current state of the ruins suggests the castle met a violent end, possibly through deliberate demolition using explosives. Writing in 1914, local historian Neary documented nine huge blocks of masonry and noted subtle undulations in the ground that likely mark the grassed-over footings of the original castle walls. He also recorded evidence of a rectangular subsidiary building positioned about twenty feet lower on the northern side, though no visible traces of this structure remain today. Neary mentioned an opening in the centre of the castle that he described as leading to a souterrain, though modern archaeological assessment suggests this interpretation is unlikely.

Perhaps most intriguingly, a painting of Doonbally Castle once existed, showing the fortress in its prime as an imposing structure comparable in scale to Dunmore Castle. While this artwork appears to be lost, it offers a tantalising glimpse of what must have been a formidable defensive position, commanding views across the Galway countryside from its elevated position on the motte. Though no architectural features survive to tell us about the castle’s specific design or layout, the sheer size and weight of the remaining masonry blocks speak to the substantial nature of the original fortification.