Shropshire Union Canal links are to the Llangollen Canal (at Hurleston Junction), the Middlewich Branch (at Barbridge Junction), which itself connects via the Wardle Canal with the Trent and Mersey Canal, and the River Dee (in Chester). With two connections to the Trent and Mersey (via the Middlewich Branch and the Staffordshire and Worcestershire Canal) the SU is part of an important circular and rural holiday route called the Four Counties Ring. The SU main line was the last trunk narrow canal route to be built in England. It was not completed until 1835 and was the last major civil engineering accomplishment of
Llangollen 1201, under the patronage of Madog ap Gruffydd Maelor of Castell Dinas Brân. The bridge at Llangollen was built across the Dee in the 16th century to replace a previous bridge built in about 1345 by John Trevor, of Trevor Hall (later Bishop of St Asaph), which replaced an even earlier bridge built in the reign of King Henry I. In the 1860s the present bridge was extended by adding an extra arch (to cross the new railway) and a two-storey stone tower with a castellated parapet. This became a café before being demolished in the 1930s to improve traffic