Historical records first mention an island stronghold in this lake as far back as 846 AD, when Viking raids and local conflicts made such defensive positions essential. Local tradition has long claimed that Ballaghanea was this ancient fortress, though archaeologists have yet to uncover definitive proof linking the current island to those early medieval annals.

What visitors can see today tells a different story entirely. The stone walls and quay structures visible on the island appear to date from the 19th century, suggesting the site saw renewed activity during Ireland's industrial age. These later additions may have been built for agricultural purposes or as part of a private estate improvement scheme, common during that period when landlords were developing their holdings around Irish lakes.

The absence of any medieval castle remains raises intriguing questions about the island's true history. If this was indeed the stronghold mentioned in 846 AD, its original structures have completely vanished; perhaps dismantled for building materials, destroyed in conflict, or simply eroded by centuries of Irish weather. Alternatively, the ancient fortress might have been on another of Lough Ramor's islands, leaving Ballaghanea's early history a blank slate until its 19th century transformation.