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Vyrnwy Aqueduct and Llanymynech

A delightful walk beside arguably the most beautiful section of the Montgomery Canal, including its biggest engineering structure and other fascinating historical features


IWA Shrewsbury District & North Wales Branch


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Location: On the England–Wales border, between Oswestry and Welshpool.

Length: About 3½ miles. 

Surface: Typical rural towpath: a narrow path on grass, wet after rain.

Parking: At Llanymynech Heritage Centre [SJ266211, satnav SY22 6EZ]. 

Refreshments: Tea, coffee, ice creams etc at the Heritage Centre when open; pubs in Llanymynech village.

Toilets: At Heritage Centre when open.

From the bus stop outside the Llanymynech Heritage Centre take Tanat Valley bus 74 (only two journeys each weekday) to Four Crosses, getting off at the crossroads.  (Both English and Welsh bus passes are valid.)  Cross the main road and walk along Canal Road to the canal bridge.  Join the towpath, walking north.

The Montgomeryshire Canal

The Montgomeryshire Canal was a locally-financed canal built primarily to convey limestone from Llanymynech and coal from Chirk and Morda to limekilns along its route.  Most of the settle­ments on the Montgomery­shire Canal had limekilns.   The quicklime made in them was used on the land to improve agricultural yields and also in making mortar for the building industry.

Having received its Act of Parliament in 1794, the canal opened from Carreghofa (where it had an end-on junction with the Llanymynech Branch of the Ellesmere Canal) to Garthmyl in 1798.  It was extended to Newtown in 1815–21.

The canal was effectively closed in 1936 as a result of a breach further north.  Restoration has continued piecemeal since 1969.  Carreghofa Locks and the toll house were restored in 1986.

Clafton Bridge canal settlement

Until the turnpike road through Four Crosses was built in conjunction with flood plain reclamation  in about 1828, this was the main road from Oswestry to Welshpool.  The settlement at Clafton Bridge was created by the canal. Two of the cottages are early 19th century, the other cottages, warehouses and wharf buildings are mid 19th century.  There used to be four limekilns here.   The winding holes either side of the bridge provided material for the embankment across the Vyrnwy valley. 


Pentreheylin Hall was built in 1830 by John James Turner, using the canal to bring in materials.

Pentreheylin Hall Bridge (98) and Pentreheylin Bridge (97) were built using ‘fish-belly’ cast iron beams to support the deck.

Pentreheylin warehouse was probably built in the early 1830s for John James Turner.  Although generally known as a salt warehouse, it probably dealt with all sorts of merchandise and produce.  Several years ago the warehouse was sympathetically converted into a dwelling.

The crossing of the River Vyrnwy

Newbridge wharf, a former coal wharf, is on the opposite side to the towpath at the southern end of the Vyrnwy Aqueduct.

The River Vyrnwy joins the river Severn four miles to the east (in a direct line, but double that with the bends in the river).  In the 18th century it was navigable to a couple of miles above here, pig iron cast in the Coalbrookdale and Ironbridge area being brought up for conversion into wrought iron. There was abundant wood to create charcoal; the fast-running streams powered waterwheels to give a really good draught for raising the temperature.

The Vyrnwy Aqueduct is the largest structure on the Montgomeryshire Canal.  Built in 1795/6 in the then traditional method: massive, with the water channel formed in  a thick layer of puddled clay contained by relatively thin masonry walls.  It gave trouble from the start, and iron ties were inserted in 1799.  By 1823 it was leaking again, and it was found that every arch was fractured.  The tie rods were removed — many had broken — and new wrought-iron rods inserted lower down in the structure.  This proved effective, and it was another sixty years before further major repair work was needed.  However, the aqueduct is now in a bad state, with repairs costing well in excess of £1½ million needed. 

Set in the embankment are two sets of flood arches, three in the southern and four in the northern.  These have been heavily rebuilt over the years.

This section of the Montgomeryshire Canal has the greatest concentration in Western Europe of floating water plantain (Luronium natans), an internationally rare plant.

Williams Bridge was flattened in 1980; it originally had fish-belly beams, like Bridges 97 & 98.  Road users would not now tolerate a hump-backed bridge here, so when the canal is restored to navigation its replacement would more likely be an electrically operated lift bridge.  The wharf here, which was sited between the two flood aqueducts, was created by Exuperius Pickering, industrialist of Cefn Mawr.  The bridge is named after Edward Williams, who was the tenant of the coal wharf from 1844.


Above Carreghofa Locks the Montgomeryshire Canal met the Llanymynech Branch of the Ellesmere Canal.  The Montgomeryshire Canal’s original Act had the canal continuing up the Tanat Valley towards the limestone quarries at Porth-y-Waen where it would have met a branch of the Ellesmere Canal to be built at a higher level than the Llanymynech Branch.  Plans changed, and neither the Ellesmere Canal nor the Montgomeryshire Canal reached Porth-y-Waen.

As first constructed, the water feeder went into the bottom of the two locks, the top one being filled from surplus water from the Ellesmere Canal.  There were often water shortages, which led to the feeder being rebuilt in 1822 to come into the canal above the lock.  The junction between the two canals was set by Act of Parliament as 35 yards above the top gate of the top lock.

Carreghofa Locks have the distinctive Montgomeryshire Canal paddle gear designed by George Buck.  Although padlocked, it still works, though it gives fast and turbulent water flows which are potentially dangerous for inexperienced users.  The locks were restored by volunteers and were reopened in 1986. 

The buildings comprise the lock-keeper’s cottage (with pig-sty), a particularly attractive house for the toll collector (this being the principal place for the collection of tolls on the Montgomeryshire Canal) and the toll office.

On 19 December 1826 Edward Perkins, the toll collector, was helping a boat through the locks when John Bagley, a youth helping the steerer, threw a brick which hit him on the head and killed him. Bagley was arrested and sent for trial to Ruthin Gaol, Carreghofa then being in Denbighshire.

Carreghofa Aqueduct

The building of the West Shropshire Mineral Railway in the mid 1860s necessitated the construction of an aqueduct, which was made up of riveted wrought-iron plates supported on cast iron columns. The slight diversion of the canal can still be seen.  This insignificant and often bankrupt railway went through various name changes, becoming the Potteries, Shrewsbury & North Wales Railway before being leased to the Cambrian Railways in 1881.

Walls Bridge

The original hump-backed bridge (93) still stands, but the traffic now crosses on a post-war bridge only a little above water level.


Limestone from the quarries in the hill above was brought by tramroads to Llanymynech wharf then loaded into boats to be taken to kilns along both the Ellesmere and Montgomeryshire Canals.  Limestone was also transported to ironworks including, after the opening of the Birmingham & Liverpool Junction Canal, to the east Shropshire industrial area.

The earliest tramroad was the one leading from the southernmost quarry to the northern (shorter) canal arm. The second tramroad and wharf date from a few years later; at a later date the route of the two tramroads was combined below the road bridge.  Wagons on the lowest part were horse-hauled; above that, the wagons were lowered down the inclines using a cable system.  The remains of stables, the tally house and the winding gear can still be seen.

The railway arrived in Llanymynech in 1860.  A long siding was built to a large top-fed lime kiln, and towards the end of the 19th century the Warren kiln (a continu­ous­ly burning kiln) was constructed.  Railway competition severely hit the canal’s limestone trade, and the tramroads were both closed by 1899.

A short section of canal has been restored and is used by a trip boat, the George Watson Buck.  Volunteers run the boat and operate a visitors’ centre on some weekend afternoons in summer.

The wharf, limekilns, inclines and quarries are now part of a heritage area, with a variety of walks with plenty of historical, industrial and nature interest.

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