These stone-lined tunnels, built during the early medieval period, served various purposes from storage chambers to places of refuge, and remain some of the most intriguing features of Ireland's archaeological landscape.

Like many souterrains found across Ireland, particularly in counties like Donegal where they're relatively common, the Roosky example likely dates from between the 6th and 12th centuries. These structures typically consist of dry-stone walled passages, often with multiple chambers, and were usually associated with above-ground ringfort settlements.