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 itself to return via Dennis Farm.

Reviews

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: 5.8 miles/9.3 km
  • Grade: Easy-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)

Highlights

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

Directions

  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 the ahead through the next rampart to reach the grassy 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 with a wicker fence.

    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 a pedestrian gate with another ahead of it.

    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 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. 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.

  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 a healthland nature reserve managed by the Cornwall Wildlife Trust. The marshy moorland in the reserve forms the source of the River Menalhyl.

  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 with 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.

    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.

  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 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.

    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 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.

  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.

  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.

  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 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!

  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 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.

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

    Many placenames 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. Follow the track back to the farm to return to the footpath into the woods on the right. Turn right 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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