That kind of embedded evidence of the building process is rarely preserved so visibly, and it gives this crossing an almost instructional quality, as though the bridge never quite stopped explaining how it was made.

According to Kelleher (1993), the bridge was rebuilt by Charles Wilks, superintendent of the nearby gunpowder mills from 1805. The connection to the mills is significant; Ballincollig was one of the largest gunpowder manufacturing complexes in the British Isles during the nineteenth century, and reliable river crossings were essential to its operation. The rebuilt structure spans the Lee on twelve semicircular arches, voussoirs being the wedge-shaped stones that lock an arch together, cut here in rough sandstone and limestone, and rising gently in height toward the centre to give the bridge its characteristic hump. Pointed breakwaters of ashlar limestone, that is, finely cut and closely fitted stonework, project upstream from the piers and rise all the way to parapet level, where they broaden into refuge niches, shallow recesses that allowed pedestrians to step aside when a cart passed. These niches are now blocked, either fully or in part. On the flood plain to the south, six smaller semicircular overflow arches handle high water, their voussoirs more roughly cut than those of the main span, with stone paving visible beneath them.

The bridge sits close to the Ballincollig Regional Park, which incorporates the ruins of the gunpowder mills complex, and the two sites together offer an unusually complete picture of early nineteenth-century industrial infrastructure along this stretch of the Lee. The overflow arches on the southern side, easy to miss if you cross without stopping, repay a closer look from the riverbank.