Cors Bodeilio National Nature Reserve, Anglesey

Internationally important wetland rich in wildlife

What's here

Coronavirus update


Our sites and most visitor facilities are open but, under the current coronavirus restrictions in Wales, this is intended only for the use of people who live locally.


You are strongly advised – in line with current Welsh Government regulations – not to drive to any of our sites to exercise unless you have specific health or mobility issues.


We have changed the normal route for some of our trails to help you maintain social distancing – please follow signs on site.



Despite its name (cors means bog in Welsh), Cors Bordeilo is in fact a fen.

After East Anglia, Wales has the UK’s second largest expanse of fens.

Cors Bodeilio is one of the three fens on Anglesey that have been designated as National Nature Reserves.

It is an internationally important nature reserve due to its unique mire (a wetland area without forest cover dominated by living, peat-forming plants).

Mineral-rich water from the surrounding limestone drains into the wetland creating the perfect conditions for a whole host of rare plants, animals and wetland birds.

Follow our waymarked walk over the boardwalk out into the fen for great views and the chance to spot some of the wildlife and the wildflower display in spring and summer.

Walking trail

The walking trail is waymarked and starts from Cors Bodeilio car park. 

Fen and Meadows Walk

1½ miles/2.3 kilometres, easy

Follow the level surfaced path to join the boardwalk.

The boardwalk takes you out into the fen and has good views.

You can continue through the reserve on an unsurfaced path - this can be muddy after wet weather.

Please note that horses may be grazing on the reserve.

Anglesey Fens National Nature Reserves

Cors Erddreiniog

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

There are over 70 National Nature Reserves in Wales.

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

  • Cors Erddreiniog (the largest)
  • Cors Bodeilio
  • Cors Goch (managed by the North Wales Wildlife Trust)

Find out more about National Nature Reserves

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

The diverse plant life at Cors Bordeilio supports a range of insects, which in turn attract large numbers of wetland birds.

Outstanding for orchids and other rarities

The fly orchid takes the prize here. It’s an extremely rare orchid in Wales – with an even rarer yellow form found here.

There are eight other orchids here including the narrow-leaved marsh orchid, marsh fragrant orchid, common twayblade, and marsh helleborine.

Typical fen species include the great fen sedge and bottle sedge. Other wetland plants thrive here such as black bog rush, sweet gale and blunt flowered rush.

Fantastic fen for minibeasts

The star has to be the rare medicinal leech – the only British leech with teeth that can bite through human skin.

There are also rare flies, water beetles, moths and 19 species of butterflies.

Easiest of all to spot are the numerous dragonflies and damselflies that hover and dart across the open water.

Reedbeds great for birds

The reserve hums and rattles in spring and summer with the calls of breeding birds like reed and sedge warblers, reed buntings, grasshopper warblers, and stonechats – you can find 130 bird species here! You may also see lapwings and curlew, or even flush out a snipe.

Closures and diversions

  • Sometimes we need to close or divert trails for your safety whilst we undertake maintenance work
  • Occasionally we may have to close a site in extreme weather, such as high winds or snow and ice due to the risk of injury to visitors or staff
  • Please always follow any instructions onsite and make sure you follow any temporary diversion signs in place

How to get here


Cors Bodeilio is 11 miles north west of Bangor. 

It is in the county of Anglesey.

Car parking is free of charge.


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 8, taking the A5025. Turn right at the end of the slip road, following signs towards Benllech. Continue for 5 miles until reaching Pentraeth. In the village, turn left at the traffic lights, signposted to Llangefni. Take the first left towards the school and follow this narrowing road for 1¼ miles and the car park is on your right.

Ordnance Survey map

Cors Bodeilio is on Ordnance Survey (OS) map 263.

The OS grid reference is SH 506 773.

Public transport

The nearest train station is in Bangor or Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (which is a request stop).
For details of public transport visit Traveline Cymru's website.

Contact details

Tel: 0300 065 3000



Related document downloads

Other places in North West Wales