Bonamargy Bridge, Bonamargy, Ballycastle, Co Antrim

A robust and handsome bridge dating from the mid-19th century, built in a neo-classical style. The bridge crosses the Margy River and comprises three segmental arches, each approximately 9 metres wide, springing from vertical masonry supports with semi-circular breakwaters located both upstream and downstream. The arch vaults are built on a slight skew. A broad stringcourse runs along the springing line, around the breakwaters, and is topped with a half-truncated cone with a capping piece. The arches are constructed with well-shaped voissoirs, and the walls are built with ashlar in large stones. A plain, weathered stringcourse, undercut with a bold cavetto, traverses the bridge walls above the voissoirs and the parapet wall, measuring approximately 47 metres on the upstream side and 57 metres on the downstream side. The abutments are terminated with widely spaced double, unbattered buttresses. The bridge has a 7-metre wide carriageway with a single footpath on the downstream side.

The current structure likely replaced a five-arch bridge built in 1719. The earlier bridge was reported as being in very good order in the Ordnance Survey Memoir, and featured prominent triangular breakwaters with refuges for pedestrians, likely just wide enough to accommodate a carriage. It was washed away around 1857. The present bridge was probably built around 1860. It is of industrial archaeological interest and stands within a conservation area. The bridge holds local historical interest.