Sitauted at the southern end of Chirk Aqueduct (NPRN 344016), an outlet sluice to drain the Llangollen Canal into the River Ceiriog via the inspection manhole into the underside of the south aqueduct arch. Canals commonly had water outlets through aqueduct structures but at 60ft/18.29m in height this is one of the most spectacular.

Louise Barker, RCAHMW, 14th September 2007.