Moore's Bridge, Hillsborough Road, Lisburn, Co Antrim

Moore's Bridge is a triple-span stone arch bridge carrying the main Lisburn-Hillsborough road over the River Lagan. Built between 1824 and 1825, it was constructed at a cost of £3,200, paid equally by the counties of Down and Antrim, as part of a new mailcoach road connecting Lisburn and Hillsborough. The bridge was originally called Hertford Bridge, after the Marquis of Hertford, the principal landowner in the area, and appears on the 1833 Ordnance Survey map under that name. It was referred to as New Bridge on maps from 1857 to 1920, and is not named Moore's Bridge until the 1939 edition of the Ordnance Survey map. The bridge is one of only two road bridges to cross the towpath of the Lagan Navigation between Belfast and Sprucefield, and unlike Ballyskeagh Bridge, the towpath and navigable channel shared the same arch, so boats did not require unhitching of horses when passing underneath.

The bridge comprises three equal-sized arches of three-centred, or semi-elliptical, profile. The abutments and piers are constructed of roughly-dressed basalt blocks laid to regular courses. The arch voussoirs are of vee-jointed cut sandstone, though the soffits have been rendered with gunite. The right-bank (south-west) arch is dry in normal circumstances; the remaining two arches span the river and the left-bank (north-east) arch also spans the former Lagan Navigation towpath, which now functions as a public footpath.

Semicircular cutwaters project from the piers on both upstream and downstream faces. These are a continuation of the piers and built of identical construction, rising to just above arch spring level. Originally they had projecting sandstone caps; except on one of the downstream piers, these caps have weathered and been replaced with brick.

The spandrels are faced with ashlar Triassic sandstone, delineated at each end by shallow basalt pilasters that extend up to the projecting parapet terminal piers. A sandstone string course runs across each face just above arch crown level.

The parapets are constructed of quarried random rubble with rounded dressed sandstone copings and terminate in projecting basalt piers capped with sandstone. According to the 1837 Ordnance Survey Memoir, the parapets were 150 paces in length on each side, with an average height of 3 feet and a thickness of 1 foot 6 inches. The memoir notes that "the principal part of the parapets are built of blackish stone quarried within about a quarter of a mile of the bridge." The parapets have been rebuilt and heightened since their original construction, though the remainder of the bridge survives substantially as originally built.

The carriageway carries two lines of traffic and two footpaths. Just beyond the end of the downstream parapet at its left-bank end, a flight of concrete steps leads down to the public footpath along the river. A galvanised metal handrail runs along the top of a random rubble wall down the side of the staircase, with a further galvanised metal handrail along the river side of the footpath through the left-bank arch.

Mounted on the road side of the downstream parapet, directly above the crown of the middle arch, is a cast-iron boundary marker post of circular cross-section with an octagonal cap, carrying the legend "Lisburn Town Council" and marking the county boundary between Antrim and Down. The survival of this boundary marker post adds to the bridge's interest.

The 1837 Ordnance Survey Memoir provides dimensions: the middle arch has a span of 35 feet and the two outer arches each span 32 feet; the breadth of road on the bridge is 42 feet including the footpath; the entire length between the two extremes of the arches is 110 feet. The memoir describes the work as "in good repair and well executed."

The bridge displays good style and proportions, reflecting the importance of the route on which it was located—a turnpike road between Belfast, Newry and Dublin. It retains its landscape setting at river level with a public footpath at the riverside and makes a positive contribution to the heritage of Lisburn.