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Pontcysyllte Aqueduct

Pontcysyllte Aqueduct is the most spectacular sight on the canal network and is the focus of the World Heritage Site.  Trevor Basin has lots of historical interest.


IWA Shrewsbury District & North Wales Branch

Pontcysyllte Aqueduct

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Distance: About a mile to cross the aqueduct and return. 

Surface: Tarmac surface, but not really wide enough on the aqueduct for a wheelchair.  Not for people afraid of heights.

Parking: At Trevor — follow the signs.  (Only vehicles for disabled persons may park in the car park immediately adjacent to Trevor Basin.)

Refreshments: The Thomas Telford Inn at Trevor Basin, and in the Pontcysyllte Chapel Tearoom in Station Road. 

Toilets: At Trevor Basin.

The walk notes assume you have parked in the main car park.  Leave by the exit at the south end of the car park.  The path here is on the route of the Ruabon Brook Railway (described below).  At the entrance to the Trevor Basin site, take the left hand path.

World Heritage status

UNESCO made the eleven miles of canal from Chirk Bank to Horseshoe Falls a World Heritage Site in July 2009.  The citation states: ‘… The Pontcysyllte Aqueduct is a pioneering masterpiece of engineering and monumental architecture … The Pontcysyllte Aqueduct and Canal are early and outstanding examples of the innovations brought about by the Industrial Revolution in Britain, where they made decisive development in transport capacities possible. They bear witness to very substantial international interchanges and influences in the fields of inland waterways, civil engineering, land-use planning, and the application of iron in structural design.’

Trevor Basin

Trevor Basin was the original terminus of the main line of the Ellesmere Canal.  The canal was originally intended to continue to Chester, but the canal company ran out of money.

The Basin was the interchange with a tramroad, which was referred to in the canal company’s minutes as the Ruabon Brook Railway.  There were rails on the long central pier and on the outside of both arms of the water, enabling coal, iron, bricks etc to be transferred from the tramroad’s wagons to boats.  A shed covering the short arm enabled goods to be loaded onto boats in the dry.  Rose Cottage, the former wharfinger’s house, is by the western arm of the basin.

The tramroad opened in 1805.  It followed a gently rising route round the valley to Cefn Mawr (‘big ridge’), where it had a hairpin bend and continued rising to Acrefair on the line what later became King Street.  It was extended to Ruabon Brook in 1808, with further extensions and branches being built in later years.  In 1861–7 the tramroad was rebuilt as a conventional standard gauge locomotive-hauled railway, with a more steeply graded and heavily engineered line being constructed direct to Acrefair.  In 1895 it was sold to the Great Western Railway. 

The bricked-up bridge led to the Plas Kynaston Canal, the first section of which was built between 1820 and 1825 by Exuperius Pickering (the younger) to serve his limekilns.  It was extended by Thomas Ward about 1830 to the total length of five-eighths of a mile.  From its far end a tramroad went through a short tunnel and round the hill to Ward’s Plas Kynaston Colliery.  The canal also served William Hazledine’s Plas Kynaston Foundry and the village of Cefn Mawr. 

Over the years various other industries grew up canalside, the most important being Robert Graesser’s phenol plant which in the 1920s became the Monsanto chemical works, at its peak employing over 2,000 people.  Its successor company, Flexsys, ceased production in 2014.  Many of the buildings have been demolished and the huge site is now north-east Wales’ biggest development site — and a particularly sensitive one as it lies within the ‘buffer zone’ of the World Heritage Site.  The canal was used to provide cooling water until 1945, and has since been filled in.  One option is to reopen it as a central feature of the redevelopment.

Scotch Hall Bridge (29) has iron ribs.  The western side arch was rebuilt to enable standard gauge wagons to pass through, but locomotives were not allowed to do so. 

The Thomas Telford Inn was called ‘Scotch Hall’ in the 19th century; it is believed to have been the house of the aqueduct’s resident engineer, Matthew Davidson.  The single story building on the south-west side of the bridge is thought to have been the accounts house and coach house during the construction of the aqueduct.

The Anglo-Welsh office & shop was an early warehouse for the general trade of the canal.

The narrow gauge railway track here is not original but a modern inaccurate interpretation: the wrong type of rail and the wrong gauge.  The tramway was actually a ‘plateway’, where the flange was on the rail and not on the wheels of wagons, and the gauge was 4ft 2in.

The canal branch to Llangollen leaves under Rhos-y-coed Bridge (31), a road bridge with cast-iron ribs.  That section of canal was built mainly to bring water from the river Dee to the canal.  Just beyond the bridge, on the left, was the platform levelled to make the aqueduct’s construction yard, later occupied by Pickering’s forge and coking kilns — the towpath changes side to avoid this site.

Trevor Basin was partly built on an artificial terrace retained by a stone wall at the south-east.  The corrugated iron stores are 20th century.  The house has been used as accommodation for canal-related workers and later as a public house.  The twin dry docks (one roofed) were built within a few years of the opening of the canal.  Behind the former store (now the visitor centre) are double wrought-iron basins on a masonry hearth to boil pitch. 

Pontcysyllte Aqueduct

Pontcysyllte Aqueduct, a 19 span cast-iron aqueduct on tapering masonry piers, is 1,007ft long with a maximum height of 126ft above the Dee.  The trough is formed from plates one inch thick, the joints made watertight with flannel impregnated with white lead. Supporting each 44ft span are four ribs, cast in three sections, bolted together with connecting plates, the outermost ribs being infilled to give the impression of a solid span.  The water goes under the towpath, easing the passage of laden boats.  The valve for emptying the water from the aqueduct is above the river.

Construction started in 1795 but halted in 1798 when the Ellesmere Canal Company was in financial difficulties.  It was then decided to replace the Trevor to Chester section with a tramroad (of which only the first few miles were made), and one suggestion was to use the part-built aqueduct for the tramroad.  Eventually it was decided to revert to the original idea of an aqueduct but to have a navigable feeder from the Dee above Llangollen.  Construction resumed in 1801 and the works were completed for a grand opening in November 1805.

The aqueduct, like the other main engineering features of this canal, was a joint project of William Jessop, the Principal Engineer, and Thomas Telford, the canal company’s General Agent (or Chief Executive, in modern terminology).  Jessop, as the consulting engineer, was the principal adviser and thus bore the responsibility for the project’s success or failure.  Telford made the original design; Jessop amended some of the dimensions; and Telford oversaw the construction. 

The stonework was erected by John Simpson and James Varley.  The ironwork was provided by William Hazledine, most of it being cast at his nearby Plas Kynaston Foundry. 

Remarkably little maintenance has had to be done in it 200 year life.  The towpath has been replaced, as have the towpath railings.  In the 1960s it was found that some of the ribs of the southernmost arch had fractured because of a slight movement of the abutment; the replacement ribs were made of steel.

The name Pontcysyllte, literally ‘the bridge which joins’, was taken from the late C17 three-arched road bridge visible upstream.


The embankment, 670yds long and up to 75ft high is an under-appreciated civil engineering triumph.  At the time of its construction it was probably the biggest earthwork in Britain since Silbury Hill (near Avebury) was built in prehistoric times.  The material came from the construction of Whitehouses Tunnel and the tunnel and long cutting at Chirk.

An optional extension of the walk is to continue for another half mile as far as Froncysyllte lime kilns. 

The cottage on the other side of the canal is late 19th century, as is the mess building for canal maintenance workers and a former workers’ institute which provided education for boat children.

Froncysyllte Lift Bridge (28) is modern but with a traditional appearance.  The lifting mechanism is hydraulic; the original lift bridge here would have been raised by pulling on a chain. The footbridge is modern.

Froncysyllte lime kilns are in three banks.  The six kilns at the eastern end of the wharf are late 19th century, the limestone being brought down from the Pen-y-Bryn quarries by an inclined railway.  The two banks of kilns to the west were built by William Hazledine in the early 19th century; these had a tramroad down from the Froncysyllte quarries.

The walk can be extended for a further four miles to create a round trip.  Continue on the towpath to the main road (B5605) bridge, then walk down the main road, across Rive Dee and up the other side.  Turn left under the railway bridge, then enter Ty Mawr Country Park.  A footpath takes you down to the river then along the bank back to the aqueduct.

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