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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Each walk includes lots of information about the history and nature along the route.
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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 return to the castle is along small lanes, tracks and footpaths across the Castle Downs.

Footpaths are quite overgrown. This has been reported to the council for cutting but this may take some time.


A great walk, I'm going to do it again in the spring when the woodland flowers are out ☺.
I am notorious for having little sense of direction and getting lost. This app was spot on, I didn't go wrong once and I liked all the information about what was around me.
Truly fabulous! The 360 degree scenic view to commence the walk was utterly breathtaking. The walk itself another glorious ramble through woodland, fields, lanes and streams. Yet again another truly fabulous ramble that we'd highly recommend.

Vital statistics

  • OS Explorer: 106
  • Distance: 6.8 miles/10.9 km
  • Grade: Moderate
  • Start from: Castle-an-dinas car park
  • Parking: Castle-an-dinas car park TR96JB
  • Recommended footwear: walking boots

OS maps for this walk

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 waymarked path until a 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.

  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 Iron Age.

  5. Go through the gap and turn right to follow along the ditch between the ramparts. Pass one gap on the left with a metal farm gate and continue to another gap leading to a wooden kissing gate.

    The purpose of enclosures within ramparts varied quite considerably. Some were built as forts to defend from marauding invaders such as the seafaring Scandanavians. 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 another kissing gate.

    The scrubby area is the site of a tungsten mine that was opened 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 the kissing gate and the one ahead of it onto a path leading downhill between the fences. Follow the path to reach another kissing gate part-way down the hill.

    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 Second World War. It still has many different modern-day uses including cutting tools, electronics, turbine blades and rocket nozzles.

  8. Go through the gate and follow the path between the fences to another kissing gate just before the line of tall trees.
  9. Go through the gate and follow the path into the woods. Follow it parallel to the fence and out of the woods to emerge onto a track.

    The bramble is a member of the rose family, and the roots are perennial but its shoots last just two years. In the first year, the shoots grow vigorously (up to 8cm in one day!) and can root to form daughter plants. In the second year, the shoots mature and send out side-shoots with flowers. The flowers are able to produce seeds without being fertilised (the flower is able to use its own pollen) as well as through pollen being transferred by insects from other plants. The word "bramble" comes from bræmaz - a word of Germanic origin meaning "prickly".

  10. 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.

    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. 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 ants caught on the barbed end of their long tongue. In fact, their tongue is so long it needs to be curled around their skull to fit inside their head.

  11. 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 with operated for just 3 years in the late 1930s extracting cobalt, copper, tin and iron.

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

    Robins are able to hover like kingfishers and hummingbirds and use this skill when feeding from bird feeders, which they are unable to cling to. Robins are also able to see magnetic fields. Receptors in their eyes make magnetic fields appear as patterns of light or colour which allows them to use the Earth's magnetic field for navigation. The tradition of robins on Christmas cards is thought to arise from Victorian postmen wearing red jackets and been nicknamed Robins.

    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.

  13. 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".

  14. 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.

  15. Cross the river and turn left. Follow the path alongside the river and around a bend to the right until you reach a track leading 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 small amount of water seeping from the remnants of the Wheal Trewolvas mine, which was located a short distance upriver.

    Metal sulphide ores within mines react with air and water to form sulphuric acid and dissolved metals. When this acidic solution (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.

  16. Bear right onto the track follow this 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.

  17. 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.

  18. Turn left onto the track and follow the path leading from it to the remains of a waymarked stile.

    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.

  19. Pass around the stile and continue ahead on the path until it eventually ends at a pedestrian gate in a fence.

    Ivy is well-known for being able to climb up almost anything but is not a parasite and is rarely a threat to healthy trees. Extracts from the plant were used in herbal remedies and still form the basis of modern-day cough medicines.

  20. Go through the gate and turn right onto the 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 powered from a low voltage source such as a car battery which charges a capacitor to release a periodic pulse of electricity; this is often audible as a quiet "crack" which is a good indicator that a fence is powered. The voltage is not high enough to cause serious injury but touching an electric fence is nevertheless unpleasant on a scale similar to stinging nettles. If you are answering the call of nature in the vicinity of an electric fence, be mindful of the conductivity of electrolyte solutions!

  21. Go through the gate and follow the driveway ahead, along the line of mushroom stones, to reach a 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.

  22. Turn left onto the lane and follow it until you reach the start of the final field on the right, just before the lane ends at a junction with the main road.

    The fields in this area are sometimes planted with daffodils.

    Growing daffodils has been an important industry in Cornwall and the Isles of Scilly for over a century. When the Great Western Railway reached Cornwall, this provided a means to export perishable goods such as fresh flowers and fish which previously would not have survived the long journey by boat or horse and cart. Out of respect for the dead, coffins were transported by the railway for free. It was therefore not unheard of for coffins filled with daffodils to arrive in London from Cornwall.

  23. Go through the gap in the hedge on the right at the waymarked post. Cross the field to a gateway in the middle of the far hedge.

    Ribwort plantain is a common weed on cultivated land with unmistakable black seed heads on the end of tall stalks often with a halo of white flowers. Generations of children have worked out that by knotting the stem, the seed head can be launched as a projectile at unsuspecting adults.

    A tea made from the leaves is a popular herbal remedy used as a cough medicine. Care should be taken where the plant is harvested as it is not only highly tolerant of high metal levels in the soil but also accumulates these. It will even tolerate and accumulate arsenic which is normally toxic to plants. It therefore has the potential to be used for cleansing soils contaminated with mine waste.

  24. Carefully cross the road to the lane opposite. Follow the lane to pass some houses and reach a stony track on the left and a small shed where home-made produce is sold.

    The settlement here is known as Blackacre.

    An acre is a unit of area dating back to mediaeval times, based on the amount of land that could be ploughed with a yoke of oxen in one day. It was standardised in 1824 as a rectangle of 4 rods (66 feet) by one furlong (660 feet). The 10:1 "letterbox" aspect ratio comes from the long, thin field shapes in mediaeval times to minimise the awkward process of turning the oxen around. In fact the name "furlong" comes from the Old English for "one furrow long". The acre has since lost its prescribed shape and now just means 43,560 square feet.

  25. Turn left and follow the stony track to a gate. Go through the kissing gate on the right of the gate and continue ahead until you reach a fork in the track.
  26. At the fork, keep left to follow the track ahead into a field. Follow along the right hedge of the field to reach an old stile with wooden poles forming a cross.

    The area of bushes on the other side of the A30 is the Goss Moor National Nature Reserve. The public footpaths leading off to the right include some underpasses beneath the A30 and these also act as corridors for wildlife such as foxes.

  27. Follow the path leading from the stile between the hedges. Continue on the path to reach a junction of footpaths with a gate leading ahead.

    The Red Fox has been present in Britain since the last Ice Age and is our most widespread and numerous predator. Foxes are omnivores: as well as hunting small mammals and birds, they will eat fruit and anything else they can scavange, in fact a major component of their diet is earthworms. This flexibility has allowed them to adapt to farmed and urban environments but also varied natural environments including the coast. In the wild, a lucky fox can live an age of about 8 but the lifespan of most foxes is typically only 1.5 - 2 years. One reason for this is that around 100,000 foxes are killed on roads every year.

  28. Go through the gate (slide the metal block up to pull back the bar) and follow the track to a gate and stile across the track, roughly 100 metres after a track departs to the left.
  29. Cross the stile to the right of the gate and follow the track ahead to emerge on a stony track beside some buildings. Keep following the track until it ends on the road.
  30. Carefully cross the road to the driveway to Castle Farm. Follow this past Castle View and onwards until you reach a point with metal gates either side of the track.

    Crows can sometimes be seen perching in the trees along the track.

    Studies have shown that crows are capable of self-discipline. If offered one piece of food now or two later, the crows will resist temptation and wait. However if the initial piece of food is a high value item such as sausage, they won't take the risk.

  31. Go through the gate on the left and once in the field go through the gate immediately on the right of it. Then bear left very slightly across the field to reach a pedestrian gate roughly in the middle of the fence opposite.

    The number of cows in Cornwall has been estimated at around 75,000 so there's a good chance of encountering some in grassy fields. If you are crossing fields in which there are cows:

    • Avoid splitting the herd as cows are more relaxed if they feel protected by the rest of the herd. Generally the best plan is to walk along the hedges.
    • Do not show any threatening behaviour towards calves (approaching them closely to take photos, making loud noises or walking between a calf and its mother) as you may provoke the mother to defend her young.
    • If cows approach you, they often do so out of curiosity and in the hope of food - it may seem an aggressive invasion of your space but that's mainly because cows don't have manners. Do not run away as this will encourage them to chase you. Stand your ground and stretch out your arms to increase your size. Usually if you calmly approach them, they will back off. It's also best to avoid making sudden movements that might cause them to panic.
    • Where possible, avoid taking dogs into fields with cows, particularly with calves. If cows charge, release the dog from its lead as the dog will outrun the cows and the cows will generally chase the dog rather than you.
  32. Go through the gate and the one on the other side of the grassy track. Bear left slightly across the field to cross towards the left corner of the far fence. As you approach, head for the pedestrian gate in the fence on the left just before you reach the field gate.

    Dandelion is a corruption of the French dent de lion (lion's tooth), which is thought to refer to the shape of the leaves. The plant is a member of the sunflower family.

    Dandelions are dispersed very effectively by the wind. The tiny parachute-like seeds can travel around five miles.

    Every part of the dandelion plant is edible and is high in Vitamin A and higher still in Vitamin K. The leaves can be eaten in salads, though their bitterness is not to everyone's taste. However, the bitterness can be reduced by blanching: drop the leaves into boiling salted water and remove after a minute and quench in ice-cold water to prevent the leaves from cooking.

  33. Go through the pedestrian gate and the one to the right of it. Then bear left slightly downhill to a pedestrian gate in the bottom fence roughly 100 metres from the left corner, just on the end of the box hedge.

    Cuckoos are migratory birds that overwinter in Africa and are first seen, or more often heard, in Cornwall during the spring. The cuckoo is well-known for laying its eggs in the nests of other bird species. The adult cuckoo is a mimic of a sparrowhawk - a predator; this causes other birds to abandon their nests, allowing the female lay her eggs. Although cuckoo eggs are larger than those already in the nest, cuckoos produce eggs in several different colour schemes to match those of several species of bird. Since the cuckoo chick is a much larger than even the full-grown foster parents (which they seem not to notice, assuming their offspring is just a bit portly), it needs to monopolize the food supply. It therefore methodically evicts all other eggs and chicks from the nest.

  34. Go through the gate and turn left onto the track. Follow it until you reach the farm with the path you followed earlier on your left. Turn left onto this and follow the path back to Castle-an-Dinas. As you enter the ramparts, keep left 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.

Help us with this walk

You can help us to keep this walk as accurate as it possibly can be for others by spotting and feeding back any changes affecting the directions. We'd be very grateful if could you look out for the following:

  • Any stiles, gates or waymark posts referenced in the directions which are no longer there
  • Any stiles referenced in the directions that have been replaced with gates, or vice-versa

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