According to records made by Fagan in 1846, this fortification was supposedly built by an Earl Baldwin of County Galway, though the connection between a Galway earl and this remote Donegal site remains unclear. The castle later passed into the hands of Squire Hamilton, who reportedly died within its walls in 1710, marking the end of an era for this mysterious stronghold.

By the time Fagan documented the local folklore in the mid-19th century, no physical trace of the castle remained; only stories passed down through generations kept its memory alive. Today, visitors to Cavan Lower will find no stone foundations, no crumbling walls, and no earthworks to mark where this castle once stood. The site has been so thoroughly erased by time that archaeologists cannot even classify what type of fortification it might have been, leaving it designated simply as an unclassified castle site.

The absence of any visible remains makes this location particularly intriguing for those interested in Ireland’s lost heritage. While many castle sites across the country retain at least some physical evidence of their existence, whether tumbled stones or defensive earthworks, this Donegal castle has achieved complete invisibility, surviving only in historical documents and the oral traditions that Fagan thought important enough to preserve. Its story serves as a reminder of how many similar structures have been completely lost to Ireland’s landscape, their histories fading with each passing generation.