The bridge is just 5.8 metres wide and runs on a north-east to south-west axis, barely wide enough for a single vehicle to pass, yet it has the kind of solidity that suggests it was built to last rather than simply to serve.

The structure is made of random rubble sandstone, meaning the stones were laid without being cut to uniform shapes, fitted together in the irregular, labour-intensive way that was common in rural Irish bridge-building before standardised masonry became the norm. The single arch is segmental, describing a shallower curve than a full semicircle, which allowed the roadway to rise and fall with less of a hump than the name might suggest. Where the arch itself meets the eye most directly, the voussoirs, the wedge-shaped stones that lock an arch in place, are cut from ashlar, that is, smooth, precisely dressed stone. The contrast between the rough rubble walls and the neat ashlar of the arch is not decorative so much as practical; the arch stones bear the compression of every crossing and needed to fit together with a precision the surrounding rubble walls did not.