Castlederg Bridge, Castlegore Road, Castlederg, Co Tyrone, BT81 7PU

Castlederg Bridge is a substantial four-span road bridge built around 1835, carrying Castlegore Road over the River Derg. It replaced an earlier seventeenth-century structure that had become too narrow and steep for modern traffic.

The bridge is constructed of ashlar sandstone throughout its main elements. The four main spans are carried on segmental-headed arches with cut stone voussoirs, the southernmost arch being noticeably smaller. The abutments, spandrels and piers are all of ashlar sandstone, with a string-course at carriageway level. The parapet walling is ashlar sandstone on the exterior, with rubble construction behind; it terminates to the north in square piers with flat sandstone coping, and is rounded in section elsewhere with sandstone coping. The arch soffits are cement rendered. Rounded V-shaped ashlar cutwaters project from the piers. The abutments splay outward at each end, enclosing stone stairs to the south-east and south-west that provide access to the riverbank. The south-west stair has been altered with replacement roughcast walling and a steel handrail, whilst the south-east retains its original wrought-iron railing. The carriageway is approximately 8 metres wide with a footpath to the west.

A rubble parapet wall continues southward from the bridge, forming a boundary wall to the riverbank and extending to two further small segmental-headed flood arches with cut stone voussoirs and cement-rendered soffits. These flood arches have been subsequently extended beneath a carpark to the east, constructed in random rubble with corrugated metal reinforcement to the soffits. Further rubble walling remains to the south-west. At the north, a recent rubble retaining wall creates a walkway at carriageway level with steps down to the riverbank.

The bridge occupies a prominent position on the main road into Castlederg, immediately south of Main Street. Urban development lies to the north and residential houses with a modern church to the south.

Historical records indicate that a bridge was present on the 1833 Ordnance Survey map. The OS Memoirs record the construction in progress, noting the bridge was to be 168 feet long with a 30-foot-wide roadway consisting of four arches. The architect contracted to build it for 700 pounds, with Sir Robert Ferguson contributing 100 pounds and the remainder to be paid by the county in six instalments. The original bridge, erected by Sir John Davis in the early seventeenth century (with a stone reportedly marked 1613), had been taken down due to its inadequate width and steep approaches. The existing random rubble parapet wall to the south of the bridge may represent remains of this earlier seventeenth-century structure, retaining little ornamentation despite later repointing. The current bridge's date of 1835 is confirmed by its styling and ornamentation, making it an excellent example of mid-nineteenth-century engineering work of considerable importance both locally and within the wider context of Castlederg's development.