Llyn Idwal

---

title: "Llyn Idwal" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["capel-curig", "llandygai", "lakes-of-conwy-county-borough", "tourism-in-conwy-county-borough", "lakes-of-gwynedd", "tourism-in-gwynedd", "lakes-of-snowdonia", "tourism-in-snowdonia", "ramsar-sites-in-wales", "oligotrophic-lakes"] description: "Lake in Conwy County Borough, Wales" topic_path: "geography/united-kingdom" source: "https://en.wikipedia.org/wiki/Llyn_Idwal" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Lake in Conwy County Borough, Wales ::

::data[format=table title="Infobox body of water"]

Field	Value
name	Llyn Idwal
image	File:Idwal Slabs at the end of Llyn Idwal.jpg
pushpin_map	Wales Conwy
location	Snowdonia, Wales
coords
lake_type	natural
basin_countries	United Kingdom
length	2115 ft
width	885 ft
area	28 acre
elevation	373 m
islands	numerous islets
extra	{{Designation list
embed	yes
designation1	Ramsar
designation1_date	7 November 1991
designation1_number	534}}
::

| name = Llyn Idwal | image = File:Idwal Slabs at the end of Llyn Idwal.jpg | caption = | image_bathymetry = |pushpin_map=Wales Conwy | caption_bathymetry = | location = Snowdonia, Wales | coords = | lake_type = natural | inflow = | outflow = | catchment = | basin_countries = United Kingdom | length = 2115 ft | width = 885 ft | area = 28 acre | depth = | max-depth = | volume = | residence_time = | shore = | elevation = 373 m | frozen = | islands = numerous islets | cities = | extra = {{Designation list | embed = yes | designation1 = Ramsar | designation1_date = 7 November 1991 | designation1_number = 534}} Llyn Idwal is a small lake (approximately 800 m by 300 m, or 28 acres) that lies within Cwm Idwal in the Glyderau mountains of Snowdonia.

It is named after Prince Idwal Foel, a grandson of Rhodri Mawr, one of the ancient Kings of Wales. Legend states that the king's unfortunate offspring was murdered by being drowned in the lake. In fact Idwal Foel died in battle against the Saxons in 942 and an alternate version claims that he was cremated beside the lake, as was the burial custom for Celtic nobility.

A number of small streams flow into Llyn Idwal from around Cwm Idwal. One small river flows out and joins the Afon Ogwen river at Pont Pen-y-Benglog near Ogwen Cottage, immediately above the Rhaeadr Ogwen waterfall. It is considered relatively oligotrophic.

Paths

The lake is easily accessible on foot via a 900-metre long stone-paved path from Ogwen Cottage on the main A5 road. Another path encircles the lake. Two paths lead from opposite sides of the lake to the top of the ridge close to the Twll Du (Devil's Kitchen), but these paths become rather steep in places. They lead to Glyder Fach and Glyder Fawr.

There is a small pebble beach at the northwest edge of Llyn Idwal which is occasionally used by visitors for recreation. Swimming is not allowed in Llyn Idwal, as it is a protected environment, and home to several protected species.

The lake lies wholly within Gwynedd County, although the eastern edge forms the boundary between the counties of Gwynedd and Conwy.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/4/40/Llyn_Idwal.jpg" caption="Llyn Idwal, summer 2007"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/a/af/Llyn_Idwal08.jpg" caption="Llyn Idwal surrounded in mist, summer 2008"] ::

References

References

1. "Llyn Idwal".
2. Ordnance Survey 1:25000 Explorer Map OL17, publ. Ordnance Survey, Southampton, 2008.
3. (January 2018)
4. "Clear-water lakes or lochs with aquatic vegetation and poor to moderate nutrient levels (Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or of the Isoëto-Nanojuncetea) - Special Areas of Conservation".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::