Route Choice and Engineering Design Preceding Construction

Although a less expensive construction course had been surveyed further east, the westerly high-ground route across the Vale of Llangollen was preferred because it would take the canal through the mineral-rich coalfields of North East Wales. The aqueduct was designed by civil engineers Thomas Telford and William Jessop for a location near Pont Cysyllte, an 18th-century road crossing. Telford's confidence in his method rested on his earlier cast-iron trough aqueduct at Longdon-on-Tern on the Shrewsbury Canal, even as the project faced considerable public scepticism, with Jessop supervising the more junior engineer's work.