Llangollen Canal has 19 stone arches, each with a 45-foot (14 metre) span. Another aqueduct carries the canal over the River Ceiriog at Chirk, and there are tunnels nearby at Whitehouses, Chirk, and Ellesmere. The canal also forms the boundary on two sides of the Fenn's, Whixall and Bettisfield Mosses National Nature Reserve. In 2009 an eleven-mile section of the canal from Gledrid Bridge near Rhoswiel through to the Horseshoe Falls, which includes Chirk Aqueduct and Pontcysyllte Aqueduct, was declared a World Heritage site by UNESCO. The canal at Hurleston Junction rises from the Shropshire Union Canal main line, through four adjacent
Llangollen flow. The bridge was also widened in 1873 and again in 1968, using masonry which blended in with the older structure. It is a Grade I listed structure and a Scheduled Ancient Monument. On the outskirts of the town is Plas Newydd ("New Mansion" or "New Place"), from 1780 the home of the Ladies of Llangollen, the Honourable Sarah Ponsonby, Lady Eleanor Butler and their maid Mary Caryll. The Pillar of Eliseg is another old monument. There is an electoral ward of the same name. This ward includes Llantysilio community and has a total population taken at the 2011 census