Today, all that remains are mounds of rubble tangled with vegetation and a few low walls, but these modest remnants tell a story of mistaken identity that confused historians for centuries. The 1842 Ordnance Survey map shows a T-shaped structure here simply marked as ‘Castle’, sitting just southwest of a country house that bore the same name.

The confusion stems from a long-standing mix-up about which castle was which. For years, historians believed this was the site of Castle Dod, with Grove White and later Healy placing it here based on Lewis’s 1837 description. However, a closer look at much earlier maps; Jobson’s from around 1589 and the Down Survey from 1655-6; reveals that Castle Harrison actually stands on the site of the former Ballyhay Castle, whilst the real Castle Dod was located further south near the present Castle Wrixon. What survived into the 18th century was described as a three-storey, double-gable-ended house that cleverly incorporated parts of the old castle into its structure, creating what Smith called in 1750 ‘a modern built house’ on the Harrison estate.

The medieval history of the site stretches back to the mid-13th century when the de Cogans held Ballyhea manor, which later passed by inheritance to the Roche family in the late 14th century. The castle’s strategic importance became clear during the turbulent rebellion of 1641-42, when it was seized from Lord Roche’s men. Though the grand house that once incorporated the castle walls is long gone, these rubble-strewn mounds remain as testament to centuries of Irish history, from medieval stronghold to Georgian mansion, all gradually reclaimed by nature.