It was built as the town's main bridge over the Jed Water in the 16th century.
The viaduct is built of cream-coloured sandstone and it spans the river with three arches, one of which normally runs over land.
The bridge was the main access into the town but it has been closed to motorised traffic for some years.
The bridge is now within the town's conservation area and many of the surrounding buildings are listed.
The Jed Water is liable to flood, so the river levels are monitored near the bridge.