The Gilsum Stone Arch Bridge carries Surry Road over the Ashuelot River in Gilsum, New Hampshire. Built in 1862-3, it is one of the highest stone-arch bridges in the state. It has a span of 47'8", and an average height over the river of 36'6". The roadway is 43'6" above the riverbed. It stands on the site of four previous bridges, where the river passes through a deep gorge. The previous bridge was also a stone-arch bridge, which was built in 1860 and collapsed (due to inferior construction) a few months later. It was designed by William Leonard Kingsbury, a local official; its builders are not known because the town's records were destroyed in a fire. The present bridge's vault is carefully constructed from dry-laid granite voussoirs that were shaped for a very precise fit, with larger st