That ridge is an esker, a long narrow mound of glacially deposited material, and it is partly because of that geology that so little of the fort now remains. The gravel beneath proved useful, and much of the esker was quarried away over the decades, taking the greater part of the archaeological site with it.

The fort itself is a rath, a type of enclosed farmstead defined by a circular earthen bank and ditch that was common across early medieval Ireland, typically associated with a single farming family and their household. On the Ordnance Survey six-inch map of 1838, Maguires Fort appears as a complete circular embanked enclosure, already named, already legible. By the 1930 edition, only the western half is shown, rendered as a faint arc of hachuring with a diameter of roughly twenty-five metres northeast to southwest and surrounded by a narrow strip of woodland. The quarrying that erased so much of the esker had done its work in the intervening century, and what the 1930 map captured was itself already a remnant. Today, a concreted area on the southwestern side of the esker is used for storing silage bales, and a trackway cuts north through what would once have been the western arc of the enclosure. Beech, ash, sycamore, hawthorn, and brambles grow across the surviving ground. There was also, at some point, a children's burial ground associated with the rath, a cillín, of the kind often found at prehistoric or early medieval sites and used informally for the interment of unbaptised infants. No trace of it remains.