It once crossed a channel that has since vanished entirely from the landscape, though it was still clearly visible on the Ordnance Survey six-inch map of 1836. That channel, roughly 200 metres long, cut across a bend in the Boyne and in doing so created a small island. The bridge was the means of reaching it.

The arch itself is built from quarried limestone and measures 4.7 metres wide, 2.6 metres in its present height, and 2.2 metres thick. Neither of its outer faces has survived intact, which leaves the structure looking somewhat incomplete, a fragment of a crossing rather than a whole one. Its date is not known. One plausible explanation for the channel itself is practical rather than decorative: it may have been cut to allow river traffic or movement along the water to bypass weirs on the main course of the Boyne. Weirs, which are low barriers built across a river to raise the water level upstream or to manage flow, were common on the Boyne and could obstruct navigation. A cut channel offering a clear alternative route would have had obvious value. Whether that fully explains the island's existence remains uncertain, and the bridge now sits as a quietly puzzling remnant of a waterway that the land has long since reclaimed.