Castle-an-dinas and Menalhyl valley circular walk

Castle-an-dinas and Menalhyl valley

A mostly circular walk from the Castle-an-dinas Iron Age hillfort with 360 degree views across Cornwall, then into the valley to the River Menalhyl, followed by wooded paths lined with primroses, bluebells and wild garlic, and lanes with vibrant wildflowers.

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The walk begins by climbing to the Castle-an-dinas hillfort and crossing the ramparts through the central enclosure. The route then passes through what was once a busy mine with overhead cableways stretching to the ramparts but is now just some quiet fields and woods. The walk descends into the Menalhyl valley and follows tracks and small lanes to reach the river near Reterth. After following the River Menalhyl, the route follows wooded paths lined by wild garlic and bluebells in spring. The route then loops back on itself to return via Dennis Farm.


  • During mid-late summer, the path leaving the castle can become overgrown with bracken and the paths along tree tunnels may get some nettle and bramble growth. Take a stick, and secateurs if you have them, to clear your way.

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Vital statistics

  • OS Explorer: 106
  • Distance: 5.8 miles/9.3 km
  • Steepness grade: Easy-moderate
  • Recommended footwear: walking boots

OS maps for this walk

OS Explorer 106 OS Explorer 106 (laminated version)

Click or tap on map for more info (blue=laminated)


  • 360-degree panoramic views from Castle-an-dinas
  • Pretty scenery along the River Menalhyl
  • Paths lined with primroses, bluebells and wild garlic in Spring


  1. Go through the waymarked pedestrian gate and follow the path to reach a gap through the ramparts of the fort.

    The uneven surface of the fields to the right is the result of mediaeval pits dug to extract tin ore. The area began being farmed around the late 19th Century and ploughing has smoothed out the pits and dumps into the surface undulations visible today.

  2. Go through the gap in the ramparts and turn left onto the path between the ramparts. Follow the path until another path leads off to the right, through the ramparts towards the centre of the fort.

    Castle An Dinas is reported in some texts as meaning "Castle of the Danes". The word "Dane" is of Germanic/Scandinavian origin, literally meaning "sandbank" (i.e. boat people who lived on low-lying land). This is actually quite accurate: the vast majority of the Scandinavian settlements in the Westcountry were along the courses of rivers. The River Menalhyl from Mawgan Porth is far too small to take a boat of any size so Castle An Dinas seems an unlikely location for a Danish settlement. Moreover this conjecture is based on Dinas sounding a bit like "Danes", but given Dinas is the Celtic word for "fort", it is likely that this is the origin.

  3. Turn right and follow the path to the stone plinth in the central area.

    From the centre of the fort, there are 360-degree panoramic views. The inscription on the plinth indicates the positions of the landmarks that can be seen on a clear day.

    Castle-an-dinas is one of the sites for midsummer bonfires.

    Until the end of the 19th Century it was traditional to celebrate St John's Eve on 23rd June in a bonfire festival known as Golowan from the Cornish word golow, meaning light. During the 20th Century, the tradition faded amid concerns over insurance claims from the fire torches and flaming tar barrels associated with the festivities. It has subsequently been revived by Old Cornwall societies, albeit in a slightly lower-risk form, involving midsummer bonfires from the 23-29th June.

  4. From the plinth, bear right to keep the bank on your left and bear left around the bank to reach a small gap in the ramparts.

    Castle-an-Dinas is one of the largest hillforts in Cornwall with a diameter of around 850 metres, situated on a hill 700 metres above sea level. It dates from the Iron Age, around 200-300 BC, when the ramparts would have been higher than today and probably topped with a wooden palisade. Inside the ramparts would have been wooden buildings, of which no trace now remains. The marshy area could have once been a well, providing water for the settlement. Also within the central area are two Bronze-Age barrows which indicate the hill was in use before the ramparts were built during the Iron Age.

    More information about Castle-an-Dinas from the Cornwall Heritage Trust.

  5. Go through the gap, cross the ditch and go through another gap through the next rampart to reach the larger space between the outer two ramparts. Turn right to follow along the grass between the ramparts. Pass a gap on the left with a metal farm gate and continue to another gap leading to a wooden pedestrian gate in a wire fence.

    The purpose of enclosures within ramparts varied quite considerably. Some were built as forts to defend from marauding invaders such as the seafaring Scandinavians. Others were defences built around small villages either as a status symbol/deterrent or for the more practical purpose of preventing domestic crimes such as theft of property by occupants of neighbouring villages. There were even some which were probably just a confined space used to stop livestock escaping!

  6. Go through the gate and follow the fence to reach the remains of a kissing gate with another ahead of it.

    A tungsten mine was opened at Castle-an-Dinas during the first half of the 20th Century when tungsten was needed by the military. The mine closed in 1950 as tungsten could be imported cheaply from the USA after WW2. An aerial ropeway (also known as a "blondin") was supported by platforms cut into the ramparts of the fort, and was removed in 1974. This was used to transport ore from the mine down the hill to the processing area near Denis Farm. The scrubby area both above and below the track is dotted with open mineshafts so it is extremely wise to stick to the track and paths, and particularly to avoid entering any fenced-off areas however large the blackberries.

  7. Go through what's left of the gate and the one ahead of it onto a path leading downhill between the fences. Follow the path to where it enters the woods.

    Tungsten (also known as Wolfram) is a rare metal which occurs as mineral compounds such as Wolframite (an oxide with iron and manganese). Tungsten is the hardest of all metals and has the highest melting point, imparting these properties when a steel alloy is made containing tungsten. This made it in great demand for arms in the World Wars. It still has many different modern-day uses including cutting tools, electronics, turbine blades and rocket nozzles.

  8. Follow the path into the woods and continue parallel to the fence and out of the woods to emerge onto a track.

    The trees here provide a habitat for (spotted) woodpeckers.

    Green woodpeckers are the largest and most colourful of the woodpeckers native to Britain and have a distinctive laughing "yaffle" call. The two species of spotted woodpecker are smaller and usually noticed from the drumming sound they make on trees although they can sometimes be heard making a short "cheep" sound.

    All of the woodpeckers bore holes in trees in which they nest, but only the spotted woodpeckers drill into trees in search of food, spending most of their time perched on a tree.

    Conversely, green woodpeckers spend most of their time on the ground, hunting for ants. The ants nests are excavated using their strong beak, and then ants are caught on the barbed end of their long tongue. In fact, their tongue is so long that it needs to be curled around their skull to fit inside their head.

  9. Turn left onto the track; follow it as it becomes a lane to reach a gate at a Y-shaped junction beside a Denis Farm sign.

    In the opposite direction, the track peters out into a footpath which leads to the Tregonetha Downs which is a heathland nature reserve managed by the Cornwall Wildlife Trust. The marshy moorland in the reserve forms the source of the River Menalhyl.

    Cornwall Wildlife Trust was founded in 1962 as the Cornwall Naturalists' Trust and was run entirely by volunteers until 1974. It was renamed in 1994 as part of a national initiative to unify the names of wildlife trusts across the country. It now manages over 50 nature reserves and has over 17,000 members with over 1,000 active volunteers.

    There's a volunteering section on the Cornwall Wildlife Trust website which includes lots of marine activities as well as things in the nature reserves.

  10. Turn right at the junction and follow the lane to reach another junction with a Tregonetha sign.

    Close to the river to the left is the site of Wheal Trewolvas which operated for just 3 years in the late 1930s extracting cobalt, copper, tin and iron.

  11. Turn left (away from Tregonetha) and follow the lane to a barn where the lane forks.

    The Cornish name for the bird is rudhek from rudh = "red" (in Cornish, "dh" is pronounced like the "th" in "with"). Cornish place names like Bedruthan, Ruthern and Redruth are all based on the colour red.

  12. Continue ahead on the main lane. Follow it until you pass a small waterfall on the right and reach a track on the left.

    The settlement of Reterth was first recorded in 1201 as Riderc. The name is thought to be from the Cornish words rid, meaning "ford", and derch meaning "clear".

  13. Turn left down the track and follow it to a bridge over the river.

    The River Menalhyl, which meets the sea at Mawgan Porth, is about 12 miles long and had a number of mills along its length. The name of the river comes from the Cornish words melyn, meaning mill, and heyl, meaning estuary.

  14. Cross the river and turn left. Follow the path alongside the river, around a bend to the right, and uphill to reach a track joining from a field gate.

    As the path turns around the bend to the right, notice the orange staining of the gravel. This is likely to be from a small amount of water seeping from the remnants of the Wheal Trewolvas mine, which was located a short distance upriver.

    When the acidic solution containing dissolved metals from mines (known as Acidic Mine Drainage) meets other water, it is diluted and the reduced acidity causes dissolved iron to precipitate out as orange or yellow hydroxides, colouring the water and sticking to anything in the watercourse. In the case of copper mines, copper stays dissolved in the water and at higher levels this can be toxic to wildlife, particularly fish.

    Where there is a large amount of water coming from a mine which is not rendered harmless by natural dilution, reed beds have been found to be very effective in treating the acidic water. Plants and bacteria in the reed bed convert the dissolved metals into insoluble compounds that are trapped within the reed bed. There are even suggestions that the metals may be commercially recoverable after they have been concentrated in the reed bed over a period of time.

  15. Bear right to continue following the track uphill until it ends on a lane.

    The settlement of Trewolvas was first recorded in 1289 as Treworwels and was already subdivided at this point into mur (great) and vyghan (little). Whichever of the two was the original settlement probably dates from the Dark Ages as the name starts with the Celtic word tre, meaning farmstead. The origin of the rest of the name is not known.

  16. Turn right onto the lane and follow it past a farmhouse on the left until you reach a track on the left where the wall ends, opposite a large barn on the right.

    If cows eat wild garlic, this flavours their milk. Whilst this is definitely not what's wanted for tea or cornflakes, the butter made from it is more useful. This means of producing garlic butter became popular in Switzerland in the 19th Century.

    Records of field names here include "Chapel Meadow" and "Lazar Park" which hint that there may have been a mediaeval chapel and hospital here.

  17. Turn left onto the track immediately after the stone wall and follow the path leading from it until it eventually ends at a pedestrian gate in a fence.

    There are snowdrops along the path where it passes the cottage.

    Snowdrops are one of the earliest plants to flower. They use energy stored in their bulbs to generate leaves and flowers during winter, whilst other plants without an energy reserve cannot compete. The downside to flowering so early is that pollinating insects are more scarce, so rather than relying exclusively on seeds, they also spread through bulb division.

    The footpath here is graded "silver" so if it's starting to become overgrown, report it to the Council for cutting using the steps below.

    To report an overgrown path, on the directions screen in the app tap on the menu next to the direction number for the problematic path (or tap on the direction number on the map screen to get the menu) and select Report Footpath Issue. The app will use the direction number to work out the parish and path number at that location and then create an email to Cornwall Council’s Countryside Team so they can contact the relevant Parish Council. If possible, take photos and attach them to the email as that will help the countryside team to see how bad it is and prioritise it.

    Footpaths in Cornwall are graded "gold", "silver" and "bronze" (bronze paths are normally dead-ends that don't link up with other paths).

    For parishes that take part in the Local Maintenance Partnership, gold paths are normally cut routinely once or twice each year. Routine cuts on gold paths are typically done in May/June, and any second cuts are usually in July - September.

    Paths graded as silver are cut at the discretion of the Parish, so these in particular need to be reported to the Parish Council (via the Countryside Access Team - - who have the contact details for each parish council) if they start to become overgrown. Also gold paths which happen to be in parishes who don't participate in the scheme are less likely to get a routine cut, but the Countryside Team can cut these themselves if they get badly overgrown.

    Blackbirds can be found in deciduous woodland, particularly where there is dense undergrowth. In the man-made landscape, hedges provide plenty of dense undergrowth and have consequently become a really important habitat for blackbirds. Moreover, many gardens have such a high density of hedges and bushes that they are able to support ten times the blackbird population versus an equivalent area of their natural woodland habitat.

  18. Go through the gate and turn right onto the grassy track. Follow it a short distance to a corner in the track beside some gates. Follow the track around the corner to the left to reach a gate onto a driveway.

    Just after the corner, the top of the fence on the right is electrified.

    Electric fences are typically powered from a low voltage source such as a car battery which charges a capacitor to release a periodic pulse of high voltage electricity. This is often audible as a quiet "crack" which is a good indicator that a fence is powered. As with the high-voltage shock caused by static electricity, the current is not high enough to cause serious injury but touching an electric fence is nevertheless unpleasant. If you are answering the call of nature in the vicinity of an electric fence, be mindful of the conductivity of electrolyte solutions!

  19. Go through the gate and turn right to join a concrete track leading almost back on yourself. Follow this until it eventually meets the lane.

    The settlement of Tresaddern was first recorded in 1302 as Tresodorn.

    Staddle Stones (also known as Mushroom Stones) were originally used to raise granary barns off the ground. These had two purposes: the first was that the elevation above the ground kept out the damp which would spoil the grain. The second was that the overhanging stone cap made it an extreme rock-climbing expedition for any mice and rats wishing to enter the barn.

  20. Merge onto the lane and follow it until you reach a junction to the right.

    Ivy is a creeping vine which is well-known for being able to climb up almost anything. With good support, an ivy plant can climb as high as 90ft. A plant can live over 400 years and on mature plants, stems can reach a diameter of over 10cm.

  21. Turn right and follow the lane to the entrance to Dennis Farm

    Many place names in Cornwall containing "Dennis" are corruptions of Dinas which is the Celtic (Cornish and Old Welsh) word for a fort or citadel. The boy's name Dennis has an altogether different origin, from Dionysus - the god of wine. St Dennis (in Cornwall) and the shortened version of it in Australia - Sydney - are both of the latter origin.

  22. Keep right to follow the track back to Dennis Farm and return to the footpath into the woods on the right. Turn right onto this and follow the path back to Castle-an-Dinas. After the kissing gate by the ramparts, follow the path through the gap then turn left to follow the grassy path between the ramparts to return directly to the car park.

    Castle-an-Dinas is managed by the Cornwall Heritage Trust.

    The Cornwall Heritage Trust (CHT) is a charity founded in 1985 to preserve and strengthen Cornish heritage. The CHT own some historic structures such as the Treffry Viaduct and also manage a number of state-owned English Heritage sites in Cornwall such as Carn Euny.

    The CHT management of some of the smaller English Heritage sites follows controversy in 1999 when the Revived Cornish Stannary Parliament pressure group removed several English Heritage signs. CHT now manage these in partnership with local communities, Natural England, Historic England and English Heritage.

    As part of the English Heritage partnership, members of the Cornwall Heritage Trust can visit the larger English Heritage sites in Cornwall (Tintagel Castle, Restormel Castle, Launceston Castle, Pendennis Castle, Chysauster etc) free-of-charge. CHT annual membership is therefore quite an economical option for anyone intending to visit multiple English Heritage sites solely in Cornwall. The family membership is particularly good value-for-money.

    More information about the Cornwall Heritage Trust.

either as a GPS-guided walk with our app (£2.99) or a PDF (£1.99)

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