Bridge, Islandreagh House, Islandreagh Td, Co. Antrim

A single-span segmental-arched stone road bridge, dating from around 1860, spans the Belfast-Ballymena Railway line on a north/south axis. This unusual bridge was originally built as part of Islandreagh House and served as a railway bridge providing access to the house and a former mill complex; its design is notable for this private railway connection. It is also part of a group of historic structures associated with Islandreagh House and holds significance within railway heritage.

The bridge features rough-hewn squared sandstone walls with sandstone ashlar quoins to the edges, displaying tooled edges and a plain projecting string-course at springing level. The segmental arch is formed from sandstone rockfaced ashlar voussoirs with tooled edges and a rendered soffit. Tapered buttresses rise to the level of the arch on both sides. A sandstone ashlar coping tops the parapet wall. The abutments continue to either side, meeting grassy railway embankments. At deck level, a pair of square piers to the north end are constructed from sandstone, topped with pyramidal capstones of ogee profile on a projecting base. These piers support wrought iron gates that form the entrance to Islandreagh House, and are flanked by curved screen walls constructed from rock-faced squared sandstone.

The bridge first appeared on the 1857 Ordnance Survey map and remained largely unchanged on subsequent maps from the 1900s and 1920s. The Belfast-Ballymena Railway opened in April 1848, with the first sod cut in November 1845 by the 10th Viscount Massereene. In 1860, the railway line was extended to serve Ballymoney, Coleraine, Portrush, and Londonderry, becoming the Belfast and Northern Counties Railway. Engineer-architect John Lanyon, son of Sir Charles Lanyon, was commissioned to design stations and likely bridges along the line from 1873.