List of lakes of Wales explained

This is a list of lakes in Wales, including those created as reservoirs. The names of most lakes in Wales start with the word "Llyn", which is Welsh for "lake". Except where otherwise referenced, all lakes listed here are named on the relevant Ordnance Survey map at 1:25000 scale.^[1]

By area

In terms of surface area, the ten largest lakes in Wales are

• Bala Lake (Llyn Tegid) — 1196acres
• Llyn Trawsfynydd — 1180acres
• Lake Vyrnwy — 1120acres
• Llyn Brenig — 894acres
• Llyn Celyn — 800acres
• Llyn Alaw — 762acres
• Claerwen Reservoir — 655acres
• Clywedog Reservoir — 601acres
• Nant-y-moch Reservoir — 525acres
• Caban Coch Reservoir — 519acres

All of the above, with the exception of Bala Lake, are reservoirs held back by dams. Bala Lake was the largest natural lake in Wales though its level has been artificially controlled by sluices since about 1804.^[2] The largest natural lake in South Wales is Llangorse Lake (Llyn Syfaddan), which is also the second largest natural lake.

By counties and county boroughs

This list of Welsh lakes ordered by principal areas (counties and county boroughs) includes lakes with a surface area of greater than 5acres, but excludes those lakes and ponds created as part of an active industrial site (i.e., works ponds) and also excludes service reservoirs used to store drinking water as part of the water supply system. Grid references identify the approximate centre of the lake or the dam in the case of artificial reservoirs. For some lakes the principal area boundary passes through a lake; in these cases the lake is represented in the list for each appropriate authority. Known occurrences include Llyn Brenig, Pontsticill Reservoir, Llwyn-on Reservoir, Cantref Reservoir and Dol-y-gaer Reservoir. All occurrences are marked with an asterisk (*).^[3]

Anglesey

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llyn Alaw	River Alaw		762disp=tableNaNdisp=table	water supply to north Anglesey
Llyn Bodgylched	No main catchment				" when adding a value-->
Llyn Cefni	Afon Cefni		167disp=tableNaNdisp=table	water supply to central Anglesey
Llyn Coron	No main catchment		69disp=tableNaNdisp=table
Llyn Dinam	No main catchment		24disp=tableNaNdisp=table
Llyn y Gors	No main catchment				" when adding a value-->	amenity (fishing)
Llyn Gwaith-glo	No main catchment				" when adding a value-->
Llyn Llygeirian	No main catchment				" when adding a value-->
Llyn Llywenan	No main catchment				" when adding a value-->	Largest natural body of water on Anglesey
Llyn Llwydiarth	Afon Braint				" when adding a value-->
Llyn Maelog	No main catchment		65disp=tableNaNdisp=table	former water supply to Rhosneigr
Llyn Pen y Parc	No main catchment				" when adding a value-->	water supply (disused)
Llyn Penrhyn	No main catchment		55disp=tableNaNdisp=table	RSPB bird reserve
Llyn Rhosddu	No main catchment				" when adding a value-->
Llyn Traffwll	No main catchment		91disp=tableNaNdisp=table
Llyn Treflesg	No main catchment				" when adding a value-->	RSPB bird reserve

Blaenau Gwent

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Blaen-y-Cwm Reservoir (Blaen Clydach Reservoir)	Ebbw River/River Clydach		50disp=tableNaNdisp=table	Reservoir, originally constructed in 1813 to supply the Nantyglo Ironworks.
Carno Reservoir	Ebbw River				" when adding a value-->	reservoir
Cwmtillery Reservoir	Ebbw River				" when adding a value-->	reservoir
Lower Boat Pond	Ebbw River		6.25disp=tableNaNdisp=table	amenity, formerly industrial supply along with smaller Upper Boat Pond
Rhyd-y-blew Pond	Ebbw River				" when adding a value-->
Parc Brynbach lake	Sirhowy River				" when adding a value-->	amenity
Shon-Sheffrey's Reservoir	Sirhowy River				" when adding a value-->	reservoir

Bridgend

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Kenfig Pool	River Kenfig		70disp=tableNaNdisp=table	natural lake
Craig yr Aber Reservoir	Nant Craig yr Aber				" when adding a value-->	man-made dam

Caerphilly

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Lower Blaen Rhymney Reservoir	Rhymney River				" when adding a value-->	reservoir
Upper Blaen Rhymney Reservoir	Rhymney River				" when adding a value-->	reservoir
Bute Town Reservoir	Rhymney River				" when adding a value-->
Caerphilly Castle moat	Rhymney River				" when adding a value-->
Nant-y-draenog Reservoir	Sirhowy River		5disp=tableNaNdisp=table	reservoir
Parc Cwm Darran Lake	Rhymney River				" when adding a value-->	amenity
Rhaslas Pond	Rhymney River				" when adding a value-->
Ffrwd Farm lake (west)	Rhymney River				" when adding a value-->	angling
Ffrwd Farm lake (east)	Rhymney River				" when adding a value-->	angling
Pen-y-fan Pond	Sirhowy River		14disp=tableNaNdisp=table	built as canal feed reservoir.

Cardiff

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cardiff Bay	River Taff/River Ely		500disp=tableNaNdisp=table	amenity
Hendre Lake	No main catchment		12disp=tableNaNdisp=table	recreation and amenity
Llanishen Reservoir	Rhymney River		59disp=tableNaNdisp=table	water supply to Cardiff
Lisvane Reservoir	Rhymney River				" when adding a value-->	water supply to Cardiff
Roath lake	Rhymney River		30disp=tableNaNdisp=table	recreation and amenity

Carmarthenshire

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llyn Brianne	River Tywi		530disp=tableNaNdisp=table	regulation reservoir
Garn Ffrwd pond?	Gwendraeth Fach		5disp=tableNaNdisp=table
Llanelli North Dock lake	Coastal waterbody				" when adding a value-->	amenity (former dock)
Llyn Llech Owen Reservoir	Gwendraeth Fawr				" when adding a value-->	amenity/reservoir
Cwm Lliedi Reservoir	Afon Lliedi				" when adding a value-->	ex water supply
Llyn y Fan Fach	River Tywi		25disp=tableNaNdisp=table	natural
Llyn Taliaris	Afon Dulais				" when adding a value-->
Lower Talley Lake	Afon Cothi		62disp=tableNaNdisp=table	natural lake
Lagoons at National Wetlands Centre	Coastal waterbodies				" when adding a value-->	conservation/wildlife
Old Castle Pond/Pond Twym	Coastal lake				" when adding a value-->	Amenity
Sandy Water	Coastal lake				" when adding a value-->	amenity
Upper Lliedi Reservoir	Afon Lliedi				" when adding a value-->	reservoir
Upper Talley Lake	Afon Cothi				" when adding a value-->	natural lake
Usk Reservoir	River Usk				" when adding a value-->	water supply
Delta Lake	Coastal lake				" when adding a value-->	amenity

Ceredigion

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llyn Bach	River Teifi				" when adding a value-->	natural lake
Llyn Berwyn	River Teifi		40disp=tableNaNdisp=table	natural lake
Llyn Craigypistyll	River Dyfi				" when adding a value-->	natural lake
Dinas Reservoir	River Rheidol				" when adding a value-->	hydroelectricity
Llyn Du	River Severn				" when adding a value-->	natural lake
Llyn Egnant	River Teifi				" when adding a value-->	water supply
Falcondale Lake	River Teifi				" when adding a value-->	amenity
Llyn Frongoch	River Ystwyth				" when adding a value-->	lead mining ?/ natural
Llyn Fyrddon Fach	River Severn				" when adding a value-->	natural lake
Llyn Fyrddon Fawr	River Severn				" when adding a value-->	natural lake
Llyn Glandwgan	River Ystwyth				" when adding a value-->	natural lake
Llyn y Gorlan	River Teifi				" when adding a value-->	water supply
Llyn Gwngi	River Severn				" when adding a value-->	natural lake
Llyn Gynon	River Severn		70disp=tableNaNdisp=table	natural lake
Llyn Hir	River Teifi				" when adding a value-->	water supply
Nant-y-moch Reservoir	River Rheidol				" when adding a value-->	hydroelectricity
Llyn Pond Gwaith	River Teifi				" when adding a value-->	Natural
Llyn Rhosrhydd	River Ystwyth				" when adding a value-->	natural lake
Llyn Syfydrin	River Rheidol				" when adding a value-->	natural lake
Llyn Teifi	River Teifi				" when adding a value-->	water supply

Conwy

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Aled Isaf Reservoir	River Clwyd		65.7disp=tableNaNdisp=table	water supply
Llyn Aled	River Clwyd		112.7disp=tableNaNdisp=table	water supply
Llyn Alwen	River Dee		65disp=tableNaNdisp=table
Alwen Reservoir	River Dee		372.9disp=tableNaNdisp=table	water supply
Llyn Bochlwyd	River Ogwen		10disp=tableNaNdisp=table
Llyn Bodgynydd	River Conwy		14disp=tableNaNdisp=table	industrial supply (disused)
Llyn Brenig	River Dee		920disp=tableNaNdisp=table	flow regulation
Llyn Coedty	River Conwy		11.6disp=tableNaNdisp=table	hydroelectricity
Llyn Conwy	River Conwy		101.3disp=tableNaNdisp=table	water supply for Llanrwst
Llyn Cowlyd	River Conwy		269disp=tableNaNdisp=table	water supply for Conwy
Llyn Crafnant	River Conwy		52disp=tableNaNdisp=table	former water supply for Trefriw and Llanrwst
Dulyn Reservoir	River Conwy		33disp=tableNaNdisp=table	water supply
Llyn Eigiau	River Conwy		120disp=tableNaNdisp=table
Llyn Elsi	River Conwy		26disp=tableNaNdisp=table	water supply for Betws-y-coed
Llyn Geirionydd	River Conwy		45disp=tableNaNdisp=table
Llyn Goddionduon	River Conwy		10disp=tableNaNdisp=table
Llyn y Foel-frech	River Clwyd				" when adding a value-->	Tiny natural lake
Ffynnon Lloer	River Ogwen		6disp=tableNaNdisp=table
Ffynnon Llugwy	River Conwy		40disp=tableNaNdisp=table
Llynnau Mymbyr	River Conwy		58disp=tableNaNdisp=table
Llyn Ogwen	River Ogwen		78disp=tableNaNdisp=table
Llyn y Parc	River Conwy		22disp=tableNaNdisp=table
Llyn-y-foel	Afon Lledr				" when adding a value-->	natural lake

Denbighshire

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Brickfields Pond	River Clwyd		8.9disp=tableNaNdisp=table	Local nature reserve
Llyn Brân			31.4disp=tableNaNdisp=table	natural
Llyn Brenig	River Dee		920disp=tableNaNdisp=table	flow regulation
Llyn Cyfynwy			17.5disp=tableNaNdisp=table
Llyn Gweryd			13.1disp=tableNaNdisp=table
Llyn Mynyllod			6.2disp=tableNaNdisp=table
Nant-y-Ffrith Reservoir	River Cegidog		12.1disp=tableNaNdisp=table
Pendinas Reservoir	River Cegidog		16.3disp=tableNaNdisp=table
Rhyl Marine Lake	River Clwyd		28.7disp=tableNaNdisp=table
unnamed lake on Rûg estate	River Dee		8.4disp=tableNaNdisp=table

Flintshire

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llyn Helyg	River Clwyd		37disp=tableNaNdisp=table
Padeswood Pool			12.6disp=tableNaNdisp=table	angling
Shotwick Lake	River Dee				" when adding a value-->	amenity
unnamed reservoir, Cilcain			5.4disp=tableNaNdisp=table
unnamed reservoir, Oakenholt			5.7disp=tableNaNdisp=table
Ysceifiog Lake			13.8disp=tableNaNdisp=table

Gwynedd

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llyn yr Adar	River Glaslyn		10disp=tableNaNdisp=table
Llyn Anafon	Afon Aber		13disp=tableNaNdisp=table	water supply
Llyn Arenig Fach			34disp=tableNaNdisp=table	natural lake
Llyn Arenig Fawr	River Dee		84disp=tableNaNdisp=table	water supply for Bala town, natural lake
Llynnau Barlwyd	River Dwyryd		NaNdisp=tableNaNdisp=table	industrial water supply
Llyn y Bi	River Mawddach		6disp=tableNaNdisp=table
Llyn Bodlyn	Afon Ysgethin		42disp=tableNaNdisp=table	water supply
Llyn Bowydd	River Dwyryd		22disp=tableNaNdisp=table	industrial water supply.
Llyn Caerwych	River Dwyryd		5disp=tableNaNdisp=table
Llyn Cau	River Dysynni		33disp=tableNaNdisp=table
Llyn Celyn	River Dee		815disp=tableNaNdisp=table	river regulation
Llyn Conglog	River Dwyryd		18disp=tableNaNdisp=table
Llyn Conglog Mawr	River Dwyryd		8disp=tableNaNdisp=table
Craiglyn Dyfi also written as Creiglyn Dyfi	River Dyfi		15disp=tableNaNdisp=table	natural corrie lake
Llyn Croesor	River Glaslyn		5disp=tableNaNdisp=table
Llyn Cwm Corsiog	Afon Dwyryd		7disp=tableNaNdisp=table	industrial water supply (disused)
Llyn Cwellyn	Afon Gwyrfai		215disp=tableNaNdisp=table	water supply, natural
Llyn Cwm Bychan	Afon Artro		25disp=tableNaNdisp=table
Llyn Cwm Dulyn	Afon Llyfni		34disp=tableNaNdisp=table	water supply
Llyn Cwmffynnon	River Conwy		20disp=tableNaNdisp=table
Llyn Cwm-mynach	River Mawddach		14disp=tableNaNdisp=table
Llyn Cwmorthin	River Dwyryd		22disp=tableNaNdisp=table
Llynnau Cwm Silyn	Afon Llyfni		NaNdisp=tableNaNdisp=table
Llyn Cwm y Foel	River Glaslyn		8disp=tableNaNdisp=table
Llyn Cwmystradllyn	River Dwyfor		98disp=tableNaNdisp=table	natural lake
Llyn Cynwch	River Mawddach		26disp=tableNaNdisp=table	amenity
Llyn Dinas	River Glaslyn		60disp=tableNaNdisp=table	natural lake
Llynnau Diwaunedd	River Conwy		NaNdisp=tableNaNdisp=table	natural lakes
Llyn Dulyn	Afon Ysgethin		5disp=tableNaNdisp=table	natural lake, reservoir
Llyn Du'r Arddu	River Seiont		5disp=tableNaNdisp=table	natural lake
Llyn Dwythwch	River Seiont		24disp=tableNaNdisp=table
Llyn y Dywarchen	Afon Gwyrfai		40disp=tableNaNdisp=table
Llyn Edno	River Glaslyn		10disp=tableNaNdisp=table
Llyn Eiddew-mawr	Afon Artro		22disp=tableNaNdisp=table
Llyn Ffynnon y Gwas	Afon Gwyrfai		10disp=tableNaNdisp=table
Llyn y Gadair	Afon Gwyrfai		50disp=tableNaNdisp=table
Llyn Gwynant	River Glaslyn		85disp=tableNaNdisp=table
Llyn Hesgyn	River Dee		5disp=tableNaNdisp=table
Llyn Hywel			13disp=tableNaNdisp=table
Llyn Idwal	River Ogwen		28disp=tableNaNdisp=table
Llyn Irddyn	Afon Ysgethin				" when adding a value-->	natural lake
Llyn Llagi	River Glaslyn		8disp=tableNaNdisp=table
Llyn Llydaw	River Glaslyn		110disp=tableNaNdisp=table
Llyn Llywelyn	River Glaslyn		6disp=tableNaNdisp=table
Llyn Mair	River Dwyryd		14disp=tableNaNdisp=table	Artificial lake
Llyn Manod	River Dwyryd		16disp=tableNaNdisp=table^[4]
Marchlyn Bach reservoir	River Seiont				" when adding a value-->
Marchlyn Mawr	River Seiont				" when adding a value-->	hydroelectricity
Llyn Mwyngil (Talyllyn Lake)	River Dysynni		220disp=tableNaNdisp=table
Llyn Nantlle Uchaf	Afon Llyfni		80disp=tableNaNdisp=table
Llyn Newydd	River Dwyryd		12disp=tableNaNdisp=table
Llyn Peris	River Seiont		95disp=tableNaNdisp=table	lower reservoir for pump storage hydro-electricity
Llyn Padarn	River Seiont		280disp=tableNaNdisp=table	natural lake used for recreation
Tanygrisiau Reservoir	River Dwyryd		95disp=tableNaNdisp=table
Llyn Tecwyn Isaf			7disp=tableNaNdisp=table
Llyn Tecwyn Uchaf	River Dwyryd		31disp=tableNaNdisp=table
Bala Lake (Llyn Tegid)	River Dee		1196disp=tableNaNdisp=table	Largest natural water in Wales
Llyn Teyrn	River Glaslyn		5disp=tableNaNdisp=table
Llyn Trawsfynydd	River Dwyryd		1180disp=tableNaNdisp=table	nuclear power (formerly) and hydroelectric energy
Llyn Tryweryn	River Dee		20disp=tableNaNdisp=table
Llyn Wylfa	Afon Mawddach		6disp=tableNaNdisp=table	natural lake

Merthyr Tydfil

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cyfarthfa Castle Lake	River Taff				" when adding a value-->	amenity
Dol-y-gaer (or Pentwyn) Reservoir *	River Taff				" when adding a value-->	water supply
Llwyn-on Reservoir *	River Taff				" when adding a value-->	water supply
Penywern Middle Pond	River Taff				" when adding a value-->	angling
Penywern Top Pond	River Taff				" when adding a value-->	angling
Pontsticill Reservoir *	River Taff				" when adding a value-->	water supply

Monmouthshire

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Llandegfedd Reservoir	River Usk		434disp=tableNaNdisp=table	water supply
Pwll Pen-ffordd-goch / Keepers Pond	River Usk				" when adding a value-->	amenity, formerly served Garn-ddyrys ironworks
Wentwood Reservoir	River Usk		41disp=tableNaNdisp=table	water supply

Neath Port Talbot

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cwmwernderi Reservoir					" when adding a value-->	reservoir
Eglwys Nunydd	River Afan		260disp=tableNaNdisp=table	industrial water supply, fishing
Furzemill Pond	River Afan		5disp=tableNaNdisp=table	former millpond?
Llyn Fach	River Neath				" when adding a value-->	Natural lake
Rheola Pond	River Neath				" when adding a value-->
larger un-named lake at Aberclwyd	River Neath				" when adding a value-->	amenity
smaller un-named lake at Aberclwyd	River Neath				" when adding a value-->	amenity

Pembrokeshire

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Bosherston Lakes	Coastal stream				" when adding a value-->	artificial
Llys-y-Frân Reservoir	Western Cleddau		212disp=tableNaNdisp=table	water supply
Rosebush Reservoir	Western Cleddau		30disp=tableNaNdisp=table	water supply

Powys

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Abernant Lake	River Irfon		5disp=tableNaNdisp=table	Created in 1903 by damming an oxbow of the Irfon
Beacons Reservoir	River Taff		52disp=tableNaNdisp=table	water supply
	River Dyfi				" when adding a value-->	Natural
Caban-coch Reservoir	River Severn		500disp=tableNaNdisp=table	water supply. See note regarding area
Cantref Reservoir *	River Taff		42disp=tableNaNdisp=table	water supply
Llyn Carw	River Wye				" when adding a value-->	tiny natural lake
Claerwen Reservoir	River Severn		664disp=tableNaNdisp=table	water supply
Llyn Clywedog	River Severn				" when adding a value-->	river regulation
Craig-goch Reservoir	River Severn		217disp=tableNaNdisp=table	water supply
Cray Reservoir	River Usk		100disp=tableNaNdisp=table	water supply
Llyn Cwm Llwch	River Usk		NaNdisp=tableNaNdisp=table	tiny glacier lake
Dol-y-gaer (or Pentwyn) Reservoir *	River Taff				" when adding a value-->	water supply
Garreg-ddu Reservoir	River Severn		500disp=tableNaNdisp=table	water supply. See note regarding area
Llyn Glanmerin	River Dyfi				" when adding a value-->	natural lake
	River Dyfi				" when adding a value-->
Llyn Gludy	River Usk				" when adding a value-->
Llan Bwch-llyn Lake	River Wye		30disp=tableNaNdisp=table	Mesotrophic lake. Area is approximate.
Llangorse Lake	River Usk		327disp=tableNaNdisp=table	natural lake, largest in South Wales
Llangynidr Reservoir	Ebbw River				" when adding a value-->	reservoir
Llyn Lluncaws	Afon Tanat				" when adding a value-->	natural lake
Llyn y Fan Fawr	River Tawe				" when adding a value-->
Upper Neuadd Reservoir	River Taff				" when adding a value-->	water supply
Penygarreg Reservoir	River Severn		124disp=tableNaNdisp=table	water supply
Pontsticill Reservoir	River Taff				" when adding a value-->	water supply
Pwll gwy-rhoc	River Clydach		5disp=tableNaNdisp=table	natural lake. Area is approximate.
Talybont Reservoir	River Usk				" when adding a value-->	water supply
Ty Mawr Pool	River Usk				" when adding a value-->	natural lake
	River Vyrnwy				" when adding a value-->	water supply
Ystradfellte Reservoir	River Neath				" when adding a value-->	water supply

Note: Caban Coch and Garreg-ddu reservoirs are separately named but form one contiguous area of water at normal levels. The area quoted is for the two combined. At high water levels, Pentwyn Reservoir is continuous with Pontsticill Reservoir, its dam being submerged.

Rhondda Cynon Taf

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cantref Reservoir *	River Taff				" when adding a value-->	water supply
Dare Valley Country Park lower lake	River Cynon				" when adding a value-->	amenity
Lluest-wen Reservoir	River Rhondda Fach				" when adding a value-->
Llwyn-on Reservoir *	River Taff		150disp=tableNaNdisp=table	water supply
Llyn Fawr	River Cynon		24disp=tableNaNdisp=table	Natural but expanded for water supply
Nant-hir Reservoir	River Cynon				" when adding a value-->
Nant-moel Reservoir	River Cynon				" when adding a value-->
Penderyn Reservoir	River Neath				" when adding a value-->
?Perthgelyn Reservoir	River Cynon				" when adding a value-->	reservoir

Swansea

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Lake Fendrod	River Tawe		13disp=tableNaNdisp=table	amenity
Lower Lliw Reservoir	River Lliw				" when adding a value-->	water supply
Oxwich Marsh Lake	coastal stream		15disp=tableNaNdisp=table	natural lake. Area is a minimum figre.
Upper Lliw Reservoir	River Lliw				" when adding a value-->	water supply
Tawe Barrage	River Tawe				" when adding a value-->	amenity
Specimen Lake	River Loughor		10disp=tableNaNdisp=table	amenity/angling

Torfaen

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Blaen Bran Reservoir (lower)	Afon Lwyd				" when adding a value-->
Coity Pond	Afon Lwyd				" when adding a value-->	former reservoir

Vale of Glamorgan

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cosmeston Lake	River Cadoxton				" when adding a value-->	amenity
Hensol Lake	River Ely				" when adding a value-->	amenity and reservoir
Hensol Mill Pond	River Ely		6disp=tableNaNdisp=table	former mill pond

Wrexham

Lake name	Catchment	Grid ref.	Area	Satatus/Use
Acres	Hectares
Cae Llwyd Reservoir	River Dee		10.6disp=tableNaNdisp=table
Chirk Castle Lake	River Dee		11.1disp=tableNaNdisp=table
Fenn's Bank Mere			8.4disp=tableNaNdisp=table
Gresford Flash	River Dee		8.2disp=tableNaNdisp=table	amenity
Hanmer Mere			44.4disp=tableNaNdisp=table	natural lake, SSSI
Monk's Pool	River Dee		5.2disp=tableNaNdisp=table
Pant-yr-ochain Lake	River Dee		14.1disp=tableNaNdisp=table
Penycae Top Reservoir	River Dee		6.2disp=tableNaNdisp=table
Ty Mawr Reservoir	River Dee		21.3disp=tableNaNdisp=table
Wynnstay Park Lake	River Dee		8.9disp=tableNaNdisp=table

By national park

Lakes and reservoirs within each of Wales' three national parks.

Brecon Beacons

Lake name	Catchment	Grid ref.	Area	Status/Use	County / County Borough(s)
Acres	Hectares
Beacons Reservoir	River Taff		52disp=tableNaNdisp=table	water supply	Powys
Cantref Reservoir *	River Taff		42disp=tableNaNdisp=table	water supply	Powys, Rhondda Cynon Taf
Cray Reservoir	River Usk		100disp=tableNaNdisp=table	water supply	Powys
Dol-y-gaer (or Pentwyn) Reservoir *	River Taff				" when adding a value-->	water supply	Powys
Llyn Gludy	River Usk				" when adding a value-->		Powys
Llangorse Lake	River Wye		327disp=tableNaNdisp=table	natural lake	Powys
Llangynidr Reservoir	Ebbw River				" when adding a value-->	reservoir	Powys
Llwyn-on Reservoir *	River Taff		150disp=tableNaNdisp=table	water supply	Merthyr Tydfil, Rhondda Cynon Taf
Llyn y Fan Fawr	River Tawe				" when adding a value-->	natural lake	Powys
Upper Neuadd Reservoir	River Taff				" when adding a value-->	water supply	Powys
Pontsticill Reservoir	River Taff				" when adding a value-->	water supply	Merthyr Tydfil, Powys
Pwll Gwy-rhoc	River Clydach		5disp=tableNaNdisp=table	natural lake. Area is approximate.	Powys
Talybont Reservoir	River Usk				" when adding a value-->	water supply	Powys
Ty Mawr Pool	River Usk				" when adding a value-->	natural lake	Powys
Usk Reservoir	River Usk				" when adding a value-->	water supply	Carmarthenshire, Powys
Ystradfellte Reservoir	River Neath				" when adding a value-->	water supply	Powys

Pembrokeshire Coast

Lake name	Catchment	Grid ref.	Area	Status/Use	Principal area/s
Acres	Hectares
Bosherston Lakes	Coastal stream				" when adding a value-->	natural lakes	Pembrokeshire
Rosebush Reservoir, Rosebush	Western Cleddau		30disp=tableNaNdisp=table	water supply	Pembrokeshire

Snowdonia

Lake name	Catchment	Grid ref.	Area	Status/Use	Principal area/s
Acres	Hectares
Llyn yr Adar	River Glaslyn		10disp=tableNaNdisp=table		Gwynedd
Llyn Anafon	Afon Aber		13disp=tableNaNdisp=table	water supply
Llyn Arenig Fach			34disp=tableNaNdisp=table	natural lake	Gwynedd
Llyn Arenig Fawr	River Dee		84disp=tableNaNdisp=table	water supply, natural lake	Gwynedd
Llynnau Barlwyd	River Dwyryd		NaNdisp=tableNaNdisp=table	industrial water supply	Gwynedd
Llyn y Bi	River Mawddach		6disp=tableNaNdisp=table		Gwynedd
Llyn Bochlwyd	River Ogwen		10disp=tableNaNdisp=table		Conwy
Llyn Bodgynydd			14disp=tableNaNdisp=table	industrial supply (disused)	Conwy
Llyn Bodlyn	Afon Ysgethin		42disp=tableNaNdisp=table	water supply	Gwynedd
Llyn Bowydd	River Dwyryd		22disp=tableNaNdisp=table	industrial water supply	Gwynedd
Llyn Caerwych	River Dwyryd		5disp=tableNaNdisp=table		Gwynedd
Llyn Cau	River Dysynni		33disp=tableNaNdisp=table		Gwynedd
Llyn Celyn	River Dee		815disp=tableNaNdisp=table	river regulation	Gwynedd
Llyn Coedty	River Conwy		11.6disp=tableNaNdisp=table	hydroelectricity	Conwy
Llyn Conglog	River Dwyryd		18disp=tableNaNdisp=table		Gwynedd
Llyn Conglog Mawr	River Dwyryd		8disp=tableNaNdisp=table		Gwynedd
Llyn Conwy	River Conwy		101.3disp=tableNaNdisp=table	water supply for Llanrwst	Conwy
Llyn Cowlyd	River Conwy		269disp=tableNaNdisp=table	water supply for Conwy	Conwy
Llyn Crafnant	River Conwy		52disp=tableNaNdisp=table	former water supply	Conwy
Creiglyn Dyfi	River Dyfi		15disp=tableNaNdisp=table	natural corrie lake	Gwynedd
Llyn Croesor	River Glaslyn		5disp=tableNaNdisp=table		Gwynedd
Llyn Cwm Corsiog			7disp=tableNaNdisp=table	industrial water supply (disused)
Llyn Cwellyn	Afon Gwyrfai		215disp=tableNaNdisp=table	water supply	Gwynedd
Llyn Cwm Bychan	Afon Artro		25disp=tableNaNdisp=table		Gwynedd
Llyn Cwm Dulyn	Afon Llyfni		34disp=tableNaNdisp=table	water supply	Gwynedd
Llyn Cwmffynnon	River Conwy		20disp=tableNaNdisp=table		Gwynedd
Llyn Cwm-mynach	River Mawddach		14disp=tableNaNdisp=table		Gwynedd
Llyn Cwmorthin	River Dwyryd		22disp=tableNaNdisp=table		Gwynedd
Llynnau Cwm Silyn	Afon Llyfni		NaNdisp=tableNaNdisp=table		Gwynedd
Llyn Cwm y Foel	River Glaslyn		8disp=tableNaNdisp=table		Gwynedd
Llyn Cwmystradllyn	River Dwyfor		98disp=tableNaNdisp=table	natural lake	Gwynedd
Llyn Cynwch	River Mawddach		26disp=tableNaNdisp=table	amenity	Gwynedd
Llyn Dinas	River Glaslyn		60disp=tableNaNdisp=table	natural lake	Gwynedd
Llynnau Diwaunedd	River Conwy		NaNdisp=tableNaNdisp=table	natural lakes	Gwynedd
Llyn Dulyn	Afon Ysgethin		5disp=tableNaNdisp=table	natural lake, reservoir	Gwynedd
Dulyn Reservoir	River Conwy		33disp=tableNaNdisp=table	water supply	Conwy
Llyn Du'r Arddu	River Seiont		5disp=tableNaNdisp=table	natural lake	Gwynedd
Llyn Dwythwch	River Seiont		24disp=tableNaNdisp=table		Gwynedd
Llyn y Dywarchen	Afon Gwyrfai		40disp=tableNaNdisp=table		Gwynedd
Llyn Edno	River Glaslyn		10disp=tableNaNdisp=table		Gwynedd
Llyn Eiddew-mawr	Afon Artro		22disp=tableNaNdisp=table		Gwynedd
Llyn Eigiau	River Conwy		120disp=tableNaNdisp=table		Conwy
Llyn Elsi	River Conwy		26disp=tableNaNdisp=table	water supply	Conwy
Llyn Ffynnon y Gwas	Afon Gwyrfai		10disp=tableNaNdisp=table		Gwynedd
Llyn-y-foel	Afon Lledr				" when adding a value-->	natural lake	Conwy
Llyn y Gadair	Afon Gwyrfai		50disp=tableNaNdisp=table		Gwynedd
Llyn Geirionydd	River Conwy		45disp=tableNaNdisp=table		Conwy
Llyn Goddionduon	River Conwy		10disp=tableNaNdisp=table		Conwy
Llyn Gwynant	River Glaslyn		85disp=tableNaNdisp=table		Gwynedd
Llyn Hesgyn	River Dee		5disp=tableNaNdisp=table		Gwynedd
Llyn Hywel			13disp=tableNaNdisp=table		Gwynedd
Llyn Idwal	River Ogwen		28disp=tableNaNdisp=table		Gwynedd
Llyn Irddyn	Afon Ysgethin				" when adding a value-->	natural lake	Gwynedd
Llyn Llagi	River Glaslyn		8disp=tableNaNdisp=table		Gwynedd
Ffynnon Lloer	River Ogwen		6disp=tableNaNdisp=table		Conwy
Ffynnon Llugwy	River Conwy		40disp=tableNaNdisp=table		Conwy
Llyn Llydaw	River Glaslyn		110disp=tableNaNdisp=table		Gwynedd
Llyn Llywelyn	River Glaslyn		6disp=tableNaNdisp=table		Gwynedd
Llyn Mair	River Dwyryd		14disp=tableNaNdisp=table		Gwynedd
Marchlyn Bach reservoir	River Seiont				" when adding a value-->		Gwynedd
Marchlyn Mawr	River Seiont				" when adding a value-->	hydroelectricity	Gwynedd
Tal-y-llyn Lake (Llyn Mwyngil)	River Dysynni		220disp=tableNaNdisp=table		Gwynedd
Llynnau Mymbyr	River Conwy		58disp=tableNaNdisp=table		Conwy
Llyn Nantlle Uchaf	Afon Llyfni		80disp=tableNaNdisp=table		Gwynedd
Llyn Newydd	River Dwyryd		12disp=tableNaNdisp=table		Gwynedd
Llyn Ogwen	River Ogwen		78disp=tableNaNdisp=table		Conwy
Llyn y Parc	River Conwy		22disp=tableNaNdisp=table		Conwy
Tanygrisiau Reservoir	River Dwyryd		95disp=tableNaNdisp=table		Gwynedd
Llyn Tecwyn Isaf			7disp=tableNaNdisp=table		Gwynedd
Llyn Tecwyn Uchaf	River Dwyryd		31disp=tableNaNdisp=table		Gwynedd
Bala Lake – (Llyn Tegid)	River Dee		1196disp=tableNaNdisp=table		Gwynedd
Llyn Teyrn	River Glaslyn		5disp=tableNaNdisp=table		Gwynedd
Llyn Trawsfynydd	River Dwyryd		1180disp=tableNaNdisp=table	nuclear power (formerly) & HEP	Gwynedd
Llyn Tryweryn	River Dee		20disp=tableNaNdisp=table		Gwynedd
Llyn Wylfa			6disp=tableNaNdisp=table		Gwynedd

By supply to England

Many Welsh lakes supply the nation itself with water, however, some lakes and reservoirs supply England.^{[5] [6]}

The main reservoirs created for this purpose include:

width=20%	Reservoir name	width=20%	Location	width=15%	Built by	width=45%	Supplies water to
Lake Vyrnwy	Powys	Liverpool Corporation	Liverpool, Cheshire and Manchester
Claerwen		Birmingham Corporation Water Department	Birmingham
Craig-goch		Birmingham Corporation Water Department	Birmingham
Pen-y-garreg		Birmingham Corporation Water Department	Birmingham
Garreg-ddu		Birmingham Corporation Water Department	Birmingham,
Caban-coch^[7]		Birmingham Corporation Water Department	Birmingham
Alwen Reservoir	Conwy	The Corporation of Birkenhead	Birkenhead^[8]
Llyn Celyn (via and Bala Lake)	Gwynedd	Liverpool Corporation Waterworks	Liverpool
	Powys	Reed and Mallick of Salisbury	Shropshire, West Midlands to Bristol

Former lakes

width=25%	Lake name	width=15%	Catchment	width=10%	Grid ref.	width=10%	Area (acres)	width=25%	Status/Use	width=15%	Principal area
Bryn-bach Pond^[9]	Sirhowy River			formerly industrial use (not same site as modern lake)	Blaenau Gwent
Cairn Mound Impounding Reservoir	River Clydach			former reservoir^[10]	Blaenau Gwent
Clyn-mil Pond^[11]	River Taff			formerly industrial use	Merthyr Tydfil
Glyn-dyrys Pond^[12]	River Taff			formerly industrial use	Merthyr Tydfil
Hirwaun Ponds^[13]	River Cynon			formerly industrial use	Rhondda Cynon Taf
Lower Neuadd Reservoir	River Taff			former reservoir (dam breached)	Merthyr Tydfil^[14]
Llyn Nantlle-isaf^[15]	Afon Llyfni			natural lake	Gwynedd
Pitwellt Pond	River Taff			former reservoir (dam breached)	Merthyr Tydfil
Rhyd-y-blew Pond (Rassa)	Ebbw River			formerly industrial use	Blaenau Gwent
Scotch Peter's Reservoir^[16]	Sirhowy River			former reservoir	Blaenau Gwent

See also

• List of standardised Welsh lake names in Snowdonia

Notes and References

1. Ordnance Survey maps. 1:25000
2. Web site: Bala Bridge Sluice Gates. Royal Commission on the Ancient and Historical Monuments of Wales. 2 September 2020. 24 March 2010.
3. Web site: Bing maps . Bing . 4 September 2020.
4. https://www.fishingpassport.co.uk/fishing/upland-llyns/llyn-manod Llyn Manod
5. Web site: UK heatwave: How much water does Wales pump to England? . bbc.co.uk . BBC . 2 September 2020.
6. Web site: Elan Valley reservoirs . People's Collection of Wales . 2 September 2020.
7. Web site: Powys Digital History Project: Elan Valley Reservoirs. 9 May 2012.
8. Web site: Future capacity to supply' . What Do They Know? . What Do They Know? . 2 September 2020.
9. Web site: Monmouthshire X.12 (Dukestown; Llechryd; Rhymni; Tredegar), Revised: 1898 to 1899, Published: 1901 . Map images . National Library of Scotland . 4 December 2020.
10. Web site: Brecknockshire XLVII.3 (Bryn Mawr; Llanelli; Llangatwg), Revised: 1915, Published: 1920 . Map images . Ordnance Survey at National Library of Scotland . 4 December 2020.
11. Web site: Glamorgan XII.6 (Merthyr Tudful), Revised: 1915, Published: 1919 . Map images . National Library of Scotland . 4 December 2020.
12. Web site: Glamorgan XII (includes: Gelli Gaer; Merthyr Tudful.), Surveyed: 1868 to 1875, Published: 1885 . Map images . National Library of Scotland . 4 December 2020.
13. Web site: Glamorgan XI.5 (Aberdar; Penderyn; Rugos), Surveyed: 1867 to 1883, Published: 1885 . Map images . National Library of Scotland . 4 December 2020.
14. Web site: Welsh Water to restore reservoir to natural state . WWT . 4 September 2020.
15. Web site: Caernarvonshire XXI.SW (includes: Llandwrog; Llanllyfni.), Surveyed: 1888, Published: 1888 . Map images . National Library of Scotland . 4 December 2020.
16. Web site: Monmouthshire XI.SW (includes: Ebbw Vale; Tredegar.), Revised: 1948 to 1949, Published: 1953 . Map images . National Library of Scotland . 4 December 2020.