Pontcysyllte Aqueduct

An aqueduct of 19 spans, which crosses the River Dee at a height of 38m. It is 307m in length. The spans are of cast iron plates which are bolted at their flanges. The trough containing the water is constructed of segmental plates with radiating flanges to the outside. The upright flanges are swept to their greatest thickness where they meet the base flanges, which are emphasized to create the architectural impression of a string course. Four cast iron arches support each span of the trough from below, the outer two being cast as ribbed plates which continue the lines of the trough ribs to suggest classical arch voussoirs, with a 'keystone' to the centre. On the east side, a towing path is supported over the waterway by curving cast iron posts and beams and wrought iron ties, leaving space for the movement of water underneath as boats pass. A cast iron handrail with vertical railings is fixed to the outside ot the towpath. There is no handrail on the western side of the trough.

The 18 piers are constructed of finely dressed stone, hollow in their upper parts. They taper towards the top in both dimensions, and end at trough level. There are small cornices from which the arches spring. The four piers in the River Dee have pronounced cutwaters. There are massive curving abutments at both ends, with handrails continued onto them. A cast iron plaque on the river bank pier on the Froncysyllte side of the Dee records the purposes of the canal enterprise and the laying of the first stone on 25 July 1795.