The structure itself is modest enough: a single segmental arch, meaning a shallow curved span rather than a full semicircle, built with rough cut voussoirs, the wedge-shaped stones that lock an arch together. It measures 6.3 metres wide at its widest point. But that width is the clue that something earlier lies beneath the present form.

The crossing appears in the Civil Survey of 1654 to 1656, one of the great Cromwellian-era land assessments of Ireland, where it is recorded as 'the fford called O Hogans mill', a ford belonging to or associated with the Hogan family. A ford was simply a shallow point in a river where people, livestock, and carts could cross on foot or wheel without a bridge. That same location shows up on the first edition Ordnance Survey six-inch map of 1840 and again on the second edition of 1954, both times labelled Hogan's Pass, suggesting the name held firm across the centuries even as the crossing itself was improved. At some point a bridge replaced the ford, and that bridge was later widened to the south. The evidence for the widening is still legible if you know where to look: a straight joint, a visible line where old stonework meets new, runs along the underside of the vault. Before that alteration, the bridge originally measured four metres wide, making the southern addition just over two metres of added roadway.