Celebrating 225 years of Chirk Aqueduct

It all began in the 1790s, as plans were being drafted for the construction of the Ellesmere Canal (later renamed the Llangollen), an ambitious project spearheaded by pioneering engineers William Jessop and Thomas Telford to connect the Rivers Mersey, Dee and Severn.

However, on the English-Welsh border, they encountered a problem: Ceiriog Valley – a scenic 12-mile gorge, running west to east along the Berwyn Mountains. Jessop and Telford’s first instinct was to build a huge earthwork embankment, but unfortunately, this was quickly vetoed by the owner of nearby Chirk Castle, who was concerned about its impact on the landscape.

The pair went back to the drawing board; the route was changed, and soon, a more ambitious solution began to take shape. They would build an aqueduct to carry the canal across the valley.

Together, Jessop and Telford came up with an innovative design, which combined traditional masonry with iron. By using iron base plates instead of the usual puddled clay, they were able to reduce the weight on the piers – the stone supports between the arches – creating a structure that was both strong and relatively light.

It was a monumental effort. In an age before cranes, diggers and power tools, everything had to be done by hand. Men had to dig, haul and manoeuvre huge quantities of stone and iron, risking life and limb, high above the valley. Gradually, piece by piece, the aqueduct began to take shape.  

In 1801, five years after the foundation stone was laid, Chirk Aqueduct was finally opened for traffic. At 700 feet long and 70 feet high, it was the tallest navigable aqueduct in the world at the time. Jessop and Telford’s innovative use of iron would prove revolutionary, paving the way for Telford’s even more spectacular Pontcysyllte Aqueduct, which opened just four years later.

Throughout the 19th century, Ellesmere Canal became a vital trade route, carrying cargoes of coal, iron and limestone between North Wales and the North West of England. But, in the latter part of the century, with the advent of railways, traffic began to dwindle. Sadly, in 1944, the canal was closed to navigation, quickly falling into disuse and disrepair. For a time, Chirk Aqueduct was largely forgotten, a sleeping giant towering over the surrounding countryside.

In the early 1960s, British Waterways took ownership of the canal, and the first shoots of recovery began to appear. In 1966, the Welsh half of Chirk Aqueduct was listed Grade II, and by the 1980s, the canal, now renamed the Llangollen Canal, had become hugely popular with leisure boaters. By the end of the decade, the English half of the aqueduct joined its Welsh counterpart as a Grade II listed structure, and it now forms part of the Pontcysyllte Aqueduct and Canal UNESCO World Heritage Site.

Thanks to ongoing support from Friends and supporters like you, we can continue to care for remarkable structures like Chirk Aqueduct. Today, 225 years after it first opened, boats are still crossing the Ceiriog Valley and new generations are discovering its remarkable story.

To celebrate this incredible milestone, we've been bringing the local community together throughout the year, with floating markets and boat trips, an historic exhibition at Chirk Town Hall, Explorers activities with local schools, and lantern-making and LEGO workshops.

The celebrations culminated on 16 October, when hundreds gathered for a spectacular lantern procession beginning at Chirk Castle and crossing the aqueduct itself, creating a fitting tribute to 225 years of engineering, heritage and community.

David Morgan, development manager at Glandŵr Cymru, says: "The anniversary lantern event at Chirk Castle is a special evening to mark what is a fantastic year celebrating the iconic Chirk Aqueduct. We've been working with our local partners, the community, our volunteers and local schools to mark this historic milestone. We have all come together to celebrate and learn more about the aqueduct and the impact it has had and will continue to play in this part of Wales.”

With your support as Friends, we can continue caring for historic structures like Chirk Aqueduct, helping to ensure these extraordinary pieces of canal history remain for generations to come. While the engineers and craftspeople who built Chirk could hardly have imagined what the canal would become, their awe-inspiring work is still enthralling us all these years later. Why not walk across Chirk Aqueduct yourself and stand where generations of boaters, engineers and visitors have stood before you? It’s wonderful to experience 225 years of canal history first-hand.