Knockcairn Bridge, Tullyrusk Road, Dundrod, Crumlin, Co Antrim, BT29

Knockcairn Bridge is a well-constructed three-arch bridge dating from the late 18th century, spanning the Glenavy River and carrying the Tullyrusk Road. Built of random rubble stone, the bridge exhibits a slight curvature to its deck and features high-angled cutwaters at each end, rising to arch spring level and capped at the base of the parapets. The segmental arches, with split stone rubble voussoirs, are inset slightly from the parapets and wing walls. The central arch is slightly wider and higher than the side arches. The parapets are coped with roughly dressed stone blocks and the deck carries a one-and-a-half lane road. The bridge, identified as Knockcairn Bridge on the 1832 Ordnance Survey six-inch map, is largely unaltered and retains significant authenticity. It is situated within an unspoilt woodland setting and has group value with Ballydonaghy Bridge (listed building HB19/01/001), which crosses the same river nearby. It is considered to be of industrial archaeological interest, and its listing reflects its age, authenticity and historic importance within the local area, alongside its stylistic merit and proportions, structural system and setting.