That original six-inch map records an inner enclosure roughly thirty metres across, itself contained within a wider outer ring bringing the overall diameter to around sixty metres, the whole thing already planted with trees at the time the surveyors passed through. A ringfort, to give it its proper name, was typically a circular earthen enclosure used as a defended farmstead during the early medieval period, broadly from the fifth to the twelfth century. The presence of a double enclosure at Garrynamann places it among the more elaborately defined examples of the type.

What makes the site quietly interesting is its continuity on the historical record. When the Ordnance Survey returned for the 1948 revision, the same concentric plan was still legible in the landscape, the tree cover presumably having deepened over the intervening century. The surrounding geography adds some context. A stream running roughly north to south passes about two hundred metres to the west, draining southward into the Kings River, which runs approximately two hundred and sixty metres beyond that. Water proximity was a practical consideration for early settlement, and this arrangement, a raised enclosed site within easy reach of fresh water, fits a pattern repeated across hundreds of ringforts throughout Leinster and beyond.