The Chirk Canal Basin is a strategically placed diamond-shaped canal basin immediately north-west of Chirk aqueduct, and south-east of the entry to Chirk tunnel to enable boats to wait for other boats to transverse the narrow sections of waterway through either of these sections. The north-western part of the basin is in a considerable cutting flanking the entrance to the tunnel and the south-eastern is held above the Ceiriog Valley by the diverging masonry abutment walls of the aqueduct. The canal from the basin over the Chirk Aqueduct and south to the foot of Welsh Frankton Locks to the south was opened in 1801 and the basin became the northern terminus of the Ellesmere canal mainline for a year until the canal northwards through the Chirk Tunnel to Froncysyllte was opened in 1802.

Iain Wright, RCAHMW, 19 April 2007.
Stephen R. Hughes, RCAHMW, 29 May 2007.