For much of the medieval period, the only crossing of the River Boyne near Navan was Babe's Bridge, some three kilometres downstream, and by 1463 that structure was already described as ruinous. The crossing at Kilcarn appears to fill the gap left behind, carrying the main road between Navan, Dunshaughlin, and Dublin across a stretch of the Boyne roughly 80 metres wide, and doing so on a scale that suggests it was always intended as a serious piece of infrastructure rather than a modest local convenience.

The bridge is thought to have been built around 1550, though the earliest written reference dates to 1599, and it appears on the Down Survey barony map of Navan compiled between 1656 and 1658. Its eleven rounded arches are not uniform: the four central arches, which span the river itself, are notably wider at 20 to 22 feet, while three arches on the eastern side and four on the western are narrower at 10 to 12 feet. The triangular cutwaters on the downstream, northern side, which are projections built to deflect the current away from the piers, include one raised to parapet level to give pedestrians a small refuge when carts or livestock were passing. The southern side of the bridge was widened at some point, adding 2.7 metres to the original 3.6-metre deck, which means the original cutwaters on that face can no longer be examined. When conservation work was carried out under the archaeological supervision of N. Brady in 2016, including the fitting of concrete girdles around the river piers, excavators found that the piers sit directly on raised veins of bedrock, a practical piece of site selection that has kept the structure standing for centuries. They also established that the wider central arches represent a redesign, the original spans having been narrower. An earlier inspection in 1984 had noted something rarer still: wicker-centring surviving on the third arch from the east. Wicker-centring refers to the temporary framework of woven material used to support an arch during construction, and the fact that traces of it remained visible after more than four centuries speaks to the conditions in which the bridge has been preserved.

The bridge was closed to vehicle traffic in 1977 and has been accessible to pedestrians since the 2016 conservation work was completed. The northern cutwaters, including the pedestrian refuge, are visible from the deck and worth examining at close quarters for the quality of the stonework.