Though no trace of it remains visible today, this mysterious fortification appears in historical records dating back to the 18th century. Richard Wilson’s 1773 survey of Bolyglass and Pallasmore Hill marks it clearly at the junction of the three townlands, suggesting it held some significance in defining these territorial boundaries.

By the time the Ordnance Survey mapped the area in 1840, the castle had vanished so completely that surveyors chose the spot for a trigonometrical station; one of those crucial measurement points used to create accurate maps of Ireland. The elevated position that once made it ideal for a defensive structure proved equally useful for surveying the surrounding landscape. Today, visitors to this windswept hilltop will find no medieval masonry or crumbling walls, just the meeting point of ancient boundaries and sweeping views across the Tipperary countryside.

The castle’s complete disappearance raises intriguing questions about its original form and fate. Was it a modest tower house that local farmers gradually dismantled for building stone, or perhaps a timber fortification that simply rotted away over the centuries? Whatever its construction, the Old Castle of Ballymoylin has left behind only its name and a dot on old maps; a reminder that Ireland’s medieval landscape was once dotted with far more fortifications than survive today.