Dromore Viaduct, off Church Street, Dromore, Co Down, BT25

Dromore Viaduct is a seven-arched railway bridge constructed around 1862, carrying stone and brick in combination over the River Lagan just west of Dromore. The bridge forms the most striking feature of the Lisburn–Banbridge railway line, a fine surviving example of Victorian railway engineering in Northern Ireland.

The structure consists of rock-faced blackstone abutments and piers embellished with rusticated and margined quoins. The blocks are generally brought to courses, though laid to regular courses on some of the piers, all of which taper slightly inwards from bottom to top. The piers flanking the river arch are distinguished by curvilinear dressed granite cutwaters at both ends. Just below the spring level of each arch, projecting stones project from the pier tops—these formerly supported the timber falsework used during construction of the arches.

All seven arches are identical in semicircular profile, each comprising six header courses of brick in their arch rings and soffits. The third and fourth arches from the north-east end span a riverside footpath opened by Banbridge District Council in 2009, while the fifth arch spans the river itself. The spandrels and parapets are built of random rubble blackstone. The parapets are coped with large rock-faced sandstone blocks, chamfered and oversailing to the outside. The terminal piers at both ends follow similar detailing.

The slightly curving deck formerly carried a single railway track, now lifted and tarmaced over. High steel fences at both ends prohibit entry to the deck. The embankment has been lowered at the south-west end, though a short length survives as far as Church Road to the north-east. Concrete mountings of former floodlights remain embedded in the ground immediately west of the bridge. Much of the structure is now covered by ivy. The bridge runs east of and parallel with the A1 dual carriageway.

The viaduct lies on the Knockmore Junction–Banbridge section of the Lisburn–Castlewellan line, opened by the Banbridge, Lisburn & Belfast Railway in July 1863. The bridge was constructed by Messrs Greene & King. Thomas Jackson, the railway company's consultant engineer, designed the stations at Hillsborough, Dromore and Banbridge, and was probably also responsible for this bridge design. Upon opening, the line was worked by the Ulster Railway Company before being amalgamated into the Great Northern Railway (Ireland) in 1876. The line eventually reached Castlewellan in 1906 under the Great Northern Railway (Ireland) and was linked to Newcastle by the Belfast & County Down Railway in the same year. The Banbridge–Castlewellan section was closed in 1955, and the remainder of the line in 1956. The viaduct is now owned and maintained by Banbridge District Council.