Coedydd Maentwrog National Nature Reserve, near Porthmadog

What's here


The oak woodland of Coedydd Maentwrog National Nature Reserve is a remnant of a vast Celtic rainforest that once extended down the western side of Britain and Ireland.

The high rainfall and spray from its steep turbulent streams maintain an almost constant humid environment under the tree canopy, supporting a rare temperate rainforest.

Many of the mosses, liverworts and lichens on the tree trunks and rocks survive only in humid areas and some are so rare that they are of international importance.

The woodland is also a great place for insects which provide food for the bats that roost and breed here, including the rare lesser horseshoe bat.

You can follow a circular walk through the woodland from the Coed Llyn Mair car park or walk to the Tan y Bwlch Station on the Ffestiniog Railway.

There is a lakeside picnic area opposite the car park which is the starting point for longer walking and cycling trails managed by Snowdonia National Park Authority.


Walking trails

The walking trails are waymarked from start to finish.

Look out for the information panel at the start of the trails.

Find out about walking trail grades.

Station Link Walk

  • Grade: Easy
  • Distance: 0.4 miles/0.6 kilometres there and back
  • Time: 30 minutes
  • Trail information: The path from the car park to Tan y Bwlch station on the western side of the river has a wide, well-made surface with occasional wet patches and a short flight of steps. There are resting places every 100m and picnic tables at the top of the climb. The path from Tan y Bwlch station to the car park on the eastern side of the river is steep and has an uneven surface – if in doubt, follow the same route back to the car park on the western side of the river.

Follow the blue waymarkers to climb gradually through the oak woodlands to Tan y Bwlch station.

This station is on the Ffestiniog Railway and has a café with toilets.


Coed Llyn Mair Walk

  • Grade: Moderate
  • Distance: 0.4 miles/0.6 kilometres
  • Time: 30-45 minutes
  • Trail information: The path has a natural surface with exposed rocks and roots, and several flights of steps.

Follow the red waymarkers on this circular walk through the ancient oak woodland descending alongside the ravine with views to the stream below.

Look out for the sculptures along the way.


What to see on the National Nature Reserve

Coedydd Maentwrog is a National Nature Reserve.

National Nature Reserves are places with some of the very finest examples of wildlife habitats and geological features.

The landscape and wildlife varies depending on which time of year you visit – here’s what to look out for.

Mosses, liverworts and lichens

Many of the mosses, liverworts and lichens which adorn the oak tree trunks and rocks here survive only in humid areas – some are so rare that they are of international importance.

The high rainfall and spray from the steep streams means the air remains humid under the shade of the trees – creating globally rare ‘temperate’ rainforests.

Stand near the ravine, where the tree canopy is thicker and a constant spray rises from the stream, and you will immediately feel the greater humidity.

This creates the perfect conditions for a dazzling 200 species of mosses and liverworts and 120 species of lichen, including the large and spectacular lungwort lichen which grows on mature trees.

Moths, bats and birdlife

The woods are also a great place for insects to live in with a staggering 286 different kinds of small moth alone.

This abundance provides food for the many bats that nest here.

On warm summer evenings, if you’re lucky, you might catch sight of the tiny and rare lesser horseshoe bat, hunting high in the woodland canopy.

In summer you may just want to sit in one of the tranquil clearings and wait for the redstarts, pied flycatchers and wood warblers to turn up – the classic ‘upland oakwood’ summer migrants.

Find out more about National Nature Reserves

There are over 70 National Nature Reserves in Wales.

Find out more about National Nature Reserves.

Meirionnydd Oakwoods

Coedydd Maentwrog is one of six large Meirionnydd Oakwoods which are protected as National Nature Reserves.

These oakwoods are as globally important and as vulnerable as some tropical rainforests and are a remnant of a vast Atlantic ’wildwood’ that once extended down the western side of Britain and Ireland.

Two of the other Meirionnydd Oakwoods may be visited with care:

Dense vegetation and steep access mean that the other three Meirionnydd Oakwoods (Coed Camlyn, Coed Cymerau, and Coed y Rhygen) are not suitable for visitors.

Eryri (Snowdonia) National Park

Coedydd Maentwrog is in Eryri (Snowdonia) National Park.

Eryri is the largest National Park in Wales and is home to picturesque towns and villages and the highest mountain in Wales.

It is looked after by the Eryri National Park Authority.

For more information about visiting Eryri (Snowdonia) go to the Eryri National Park Authority website.

Visiting safely

We want you to return home safely after your visit here.

You are responsible for your own safety as well as the safety of any children and animals with you during your visit.

Please note:

  • Narrow gauge railway line with frequent trains – never walk on the railway track.
  • Steep slopes, cliffs and crags – wear appropriate footwear, keep to paths and take care.

For advice and tips to help you plan your visit here go to Visiting our places safely.

Changes to visitor facilities

See the top of this webpage for details of any planned closures or other changes to visitor facilities here.

For your safety, always follow instructions from staff and signs including those for trail diversions or closures.

We may divert or close trails whilst we undertake maintenance work or other operations and we may need to close other visitor facilities temporarily.

In extreme weather, we may close facilities at short notice due to the risk of injury to visitors and staff.

How to get here

Coedydd Maentwrog National Nature Reserve is 7 miles north east of Porthmadog.


The postcode is LL41 3AQ.

Please note that this postcode may not take you to the car park if you use a sat nav or navigation app.

We suggest you follow the directions below or use the Google map on this page which has a pin on the car park’s location.


Take the A487 from Porthmadog to Maentwrog.

Turn left on to the B4410 at the Oakeley Arms pub and, after about 500 metres, the Coed Llyn Mair car park is on the right.


View this place on the What3Words website.

Ordnance Survey

The Ordnance Survey (OS) grid reference for the Coed Llyn Mair car park is SH 652 413 (Explorer Map OL 18).

Public transport

The nearest mainline railway station is in Penrhyndeudraeth.

For details of public transport go to the Traveline Cymru website.


Parking is free of charge.

Overnight parking is not permitted.

Contact details

There are no staff at this location.

Contact our customer team for general enquiries during office hours, Monday to Friday.

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