This is a large compound aqueduct built by Thomas Telford and it carries the Llangollen Canal (formerly the Ellesmere Canal) over the river Ceiriog at Chirk, which is situated to the south of Ruabon.
Chirk Aqueduct in the foreground, 1980s.
Although the aqueduct is of masonry construction, the water is carried in a cast-iron trough. The canal is around 70 feet above the river and the aqueduct opened in 1801.
The railway viaduct on the far side is both longer and higher.