Cors Erddreiniog National Nature Reserve, Anglesey

What's here


Cors Erddreiniog is the largest of Anglesey’s three fen National Nature Reserves.

Roam its fens and heaths and you will discover a diversity of wildlife difficult to find anywhere else in Britain.

Wales has the UK's second largest expanse of fens after East Anglia.

This type of threatened wetland is very rare – in fact, because of the incredible range of wildlife it plays host to, these reserves are protected by a range of designations.

Walking trail

The walking trail is waymarked from the reserve entrance.

Look out for the information panel at the reserve entrance.

Find out about walking trail grades.

Fen and Pond Walk

  • Grade: Easy
  • Distance: 3¼ miles/5.2 kilometres (there and back from road in Capel Coch)
  • Time: 1½ hours
  • Trail information: To reach the reserve entrance you need to walk down a narrow track from the village of Capel Coch. The paths are generally unsurfaced and can be muddy after wet weather. 

Enjoy fenland views and the wildflower display in spring and summer.

Listen out for the calls of reedbed birds in early summer, too.

What to see on the National Nature Reserve

Cors Erddreiniog 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.

Fenland habitat

Bogs are fed solely from rainwater, while fens are also fed by streams and groundwater.

Mineral-rich water from the porous limestone rocks that surround the Anglesey Fens drains into them creating the perfect conditions for a whole host of rare plants and animals.

The valley bottom was once a lake, the remains of which you can still see at Llyn yr Wyth Eidion (Lake of the Eight Oxen).

Most of this area is now deep peat bog, fed by lime-rich springs.

Extensive ditches criss-cross the reserve, dug by hand over 100 years ago. These attempts at land improvement lowered the water table for grazing livestock, but also encouraged a rich range of plants.

As well as fen, you will also notice other distinctive habitats like wet heath – a riot of colour when the heather and gorse are in bloom.

In spring the hazel woodland is carpeted with primrose, wood anemone, violet and early purple orchid.

Reedbeds great for birds

You can find up to 150 bird species here.

The reserve hums and rattles in spring and summer with the calls of breeding birds like:

  • reed and sedge warblers
  • reed buntings
  • grasshopper warblers
  • stonechats

You may also see breeding lapwings and curlew flying over the reserve, or even flush out a snipe.


Orchids are the fen’s speciality.

With the exception of a handful of other sites in north Wales, Cors Erddreiniog is unique in Britain for the variety of species you will find here.

Keep an eye open especially for:

  • the rare narrow-leaved marsh orchid
  • marsh fragrant orchid
  • lesser butterfly orchid
  • fly orchid

Fantastic fen for minibeasts

There is a tiny, whorled snail here found at only three sites in Britain.

Butterflies are plentiful, such as the small pearl-bordered fritillary, marsh fritillary and the small copper.

Easiest of all to spot are the numerous dragonflies and damselflies (20 species have been seen here) that hover and dart across the reserve.

National Nature Reserves in Wales

There are over 70 National Nature Reserves in Wales.

Three of the fens on Anglesey have been designated as National Nature Reserves:

Find out more about National Nature Reserves

Find out more about the Anglesey and Llŷn Fens LIFE Project Wildlife highlights

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:

  • Deep water – keep away from the water’s edge and do not swim.
  • Muddy paths in wet weather – wear footwear with a good grip.
  • Livestock graze parts of the walks – do not approach or try to feed them: keep dogs under close control, move round the herd and shut gates behind you.
  • Wildfowl shooting takes place from September to February – please obey all signs.
  • If you see an adder do not approach it.

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

Cors Erddreiniog is 16 miles north west of Bangor.


To reach the reserve entrance you need to walk down a narrow track from the village of Capel Coch.

The postcode for Capel Coch is LL77 7UR.

Please note that this postcode may not take you to Capel Coch 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 shows Capel Coch’s location.


Take the A4087 from Bangor, continue to join the A55 heading towards Holyhead, going over the Britannia Bridge and onto Anglesey.

Leave the A55 at junction 6, heading onto the A5114 to Llangefni.

Take the B5111 out of the Llangefni one-way system towards Llannerch-y-medd. Continue through the village of Rhosmeirch and after approximately 1 mile, turn right, signposted to Capel Coch.

Continue for a further 2 miles into the village of Capel Coch.

To reach the reserve entrance you need to walk down a narrow track from the village of Capel Coch.


View this place on the What3Words website.

Ordnance Survey

The Ordnance Survey (OS) grid reference for the start of the trail is SH 463 819 (Explorer Map 263).

Public transport

The nearest mainline railway station is in Bangor or Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (which is a request stop).

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


There is no car park at the reserve and access is on foot via a narrow track from the village of Capel Coch.

There is limited roadside parking in Capel Coch - please park considerately.

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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