The Horseshoe Falls are a near-crescent shaped weir placed in the abraided bed of the River Dee, approximately 2km above Llangollen, at a sharp bend above rapids. They were originally promoted by William Jessop, engineer to the Ellesmere Canal Company, in 1795, and constructed by Thomas Telford, chief engineer from 1804 to 1806 to impound water to feed, via sluices, into the head of the Llangollen Branch of the canal system. The width of the river bed provided an adequate reservoir, and was itself controlled at distance by sluices on the headwaters of the river at Llyn Tegid as originally proposed by Jessop in his report of 17th July 1795.

The falls were essential to the efficient operation of a complicated and heavily used canal network and represent one of the first river regulation schemes anywhere in Britain. Water was drawn off the fast flowing River Dee into the Llangollen Canal which acted principally as a feeder for the Ellesmere Canal. The weir was rebuilt in 1821 after being partially destroyed by floods. Today 6 million gallons a day are metered into the canal. The falls are more J-shaped than horseshoe so the name may refer to the horseshoe like bend in the river.

The weir itself is a 140.2m long masonry structure sloped down to a 1.2m high vertical face with a capping of bullnosed cast iron sections in 2.75m lengths. The canal water is drawn off on a high level channel to the north. A sluice gate midway along has been removed. The channel curves left under a modern footbridge and is then culverted under a modern pumphouse into the canal. The course of the river on the eastern side above the weir is extended to a stone lined pound with sluices before entering the canal. A gauging station has more recently been located above the junction at the head of the canal.

It is important as a fine early nineteenth century weir, part of one of the earliest river regulation schemes carried out in Britain, and of group value with other listed structures on the Llangollen Canal.

Sources:
W J Silverwright, "Civil Engineering Heritage: Wales and Western England", 1986, p 35-36;
Hadfield C, 'The Canals of The West Midlands', (David & Charles, Newton Abbot), 2nd. Ed. 1969, p 169;
Hadfield C, Thomas Telford's Temptation, 1993, pp34-35;
Hadfield C and Skempton A W, William Jessop, Engineer. n.d. pp151-2;
Hubbard E, Clwyd, Buildings of Wales series, 1986, p197;
Hughes S, 'The Industrial Archaeology of the Montgomeryshire Canal' (Aberystwyth), 1981, p32.
Sivewright W J, Civil Engineering Heritage, Wales and Western England, 1986, pp35-36.
Wilson E, 'The Ellesmere and Llangollen Canal', 1975 (Phillimore, Chichester), p.3

Stephen R. Hughes, RCAHMW, 23.03.2007.