List of lakes of Wales

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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.

This list of Welsh lakes ordered by principal areas (counties and county boroughs) includes lakes with a surface area of greater than , 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 (*).

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlyn AlawRiver Alaw762water supply to north AngleseyLlyn BodgylchedNo main catchmentLlyn CefniAfon Cefni167water supply to central AngleseyLlyn CoronNo main catchment69Llyn DinamNo main catchment24Llyn y GorsNo main catchmentamenity (fishing)Llyn Gwaith gloNo main catchmentLlyn LlygeirianNo main catchmentLlyn LlywenanNo main catchment Largest natural body of water on AngleseyLlyn LlwydiarthAfon BraintLlyn MaelogNo main catchment65former water supply to RhosneigrLlyn Pen y ParcNo main catchmentwater supply (disused)Llyn PenrhynNo main catchment55RSPB bird reserveLlyn RhosdduNo main catchmentLlyn TraffwllNo main catchment91Llyn TreflesgNo main catchmentRSPB bird reserve

Lake nameCatchmentGrid ref. Area (acres)Status/UseBlaen y Cwm Reservoir (Blaen Clydach Reservoir)Ebbw River/River Clydach50Reservoir, originally constructed in 1813
to supply the Nantyglo Ironworks. Carno ReservoirEbbw RiverreservoirCwmtillery ReservoirEbbw RiverreservoirLower Boat PondEbbw River6.25amenity, formerly industrial supply along with smaller Upper Boat PondRhyd y blew PondEbbw RiverParc Brynbach lakeSirhowy RiveramenityShon Sheffrey's ReservoirSirhowy Riverreservoir

Lake nameCatchmentGrid ref. Area (acres)Status/UseKenfig PoolRiver Kenfig70natural lakeCraig yr Aber ReservoirNant Craig yr Aberman made dam

Lake nameCatchmentGrid ref. Area (acres)Status/UseLower Blaen Rhymney ReservoirRhymney RiverreservoirUpper Blaen Rhymney ReservoirRhymney RiverreservoirBute Town ReservoirRhymney RiverCaerphilly Castle moatRhymney RiverNant y draenog ReservoirSirhowy River5reservoirParc Cwm Darran LakeRhymney RiveramenityRhaslas PondRhymney RiverFfrwd Farm lake (west)Rhymney RiveranglingFfrwd Farm lake (east)Rhymney RiveranglingPen y fan PondSirhowy River14built as canal feed reservoir.

Lake nameCatchmentGrid ref. Area (acres)Status/UseCardiff BayRiver Taff/River Ely500amenityHendre LakeNo main catchment12recreation and amenityLlanishen ReservoirRhymney River59water supply to CardiffLisvane ReservoirRhymney Riverwater supply to CardiffRoath lakeRhymney River30recreation and amenity

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlyn BrianneRiver Tywi530regulation reservoirGarn Ffrwd pond?Gwendraeth Fach5Llanelli North Dock lakeCoastal waterbodyamenity (former dock)Llyn Llech Owen ReservoirGwendraeth Fawramenity/reservoirCwm Lliedi ReservoirAfon Lliediex water supplyLlyn y Fan FachRiver Tywi 25 naturalLlyn TaliarisAfon DulaisLower Talley LakeAfon Cothi62natural lakeLagoons at National Wetlands CentreCoastal waterbodies conservation/wildlifeOld Castle Pond/Pond TwymCoastal lakeAmenitySandy WaterCoastal lakeamenityUpper Lliedi ReservoirAfon LliedireservoirUpper Talley LakeAfon Cothinatural lakeUsk ReservoirRiver Uskwater supplyDelta LakeCoastal lakeamenity

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlyn BachRiver Teifinatural lakeLlyn BerwynRiver Teifi40natural lakeLlyn CraigypistyllRiver Dyfinatural lakeDinas ReservoirRiver Rheidolhydroelectricity Llyn DuRiver Severnnatural lakeLlyn EgnantRiver Teifiwater supplyFalcondale LakeRiver TeifiamenityLlyn FrongochRiver Ystwythlead mining ?/ naturalLlyn Fyrddon FachRiver Severnnatural lakeLlyn Fyrddon FawrRiver Severnnatural lakeLlyn GlandwganRiver Ystwythnatural lakeLlyn y GorlanRiver Teifiwater supplyLlyn GwngiRiver Severnnatural lakeLlyn GynonRiver Severn70natural lakeLlyn HirRiver Teifiwater supplyNant y moch ReservoirRiver Rheidolhydroelectricity Llyn Pond GwaithRiver Teifi NaturalLlyn RhosrhyddRiver Ystwythnatural lakeLlyn SyfydrinRiver Rheidolnatural lakeLlyn TeifiRiver Teifiwater supply

Lake nameCatchmentGrid ref. Area (acres)Status/UseAled Isaf ReservoirRiver Clwyd65.7water supplyLlyn AledRiver Clwyd112.7water supplyLlyn AlwenRiver Dee65Alwen ReservoirRiver Dee372.9water supplyLlyn BochlwydRiver Ogwen10Llyn BodgynyddRiver Conwy14industrial supply (disused)Llyn BrenigRiver Dee920 flow regulationLlyn CoedtyRiver Conwy11.6 hydroelectricityLlyn ConwyRiver Conwy101.3water supply for LlanrwstLlyn CowlydRiver Conwy269 water supply for ConwyLlyn CrafnantRiver Conwy52former water supply for Trefriw and LlanrwstDulyn ReservoirRiver Conwy33water supplyLlyn EigiauRiver Conwy120Llyn ElsiRiver Conwy26water supply for Betws y coedLlyn GeirionyddRiver Conwy45Llyn GoddionduonRiver Conwy10Llyn y Foel frechRiver Clwyd Tiny natural lakeFfynnon LloerRiver Ogwen6Ffynnon LlugwyRiver Conwy40Llynnau MymbyrRiver Conwy58Llyn OgwenRiver Ogwen78Llyn y ParcRiver Conwy22Llyn y foelAfon Lledrnatural lake

Lake nameCatchmentGrid ref. Area (acres)Status/UseBrickfields PondRiver Clwyd8.9Local nature reserveLlyn Brân31.4 naturalLlyn BrenigRiver Dee920 flow regulationLlyn Cyfynwy17.5Llyn Gweryd13.1Llyn Mynyllod6.2Nant y Ffrith ReservoirRiver Cegidog12.1Pendinas ReservoirRiver Cegidog16.3Rhyl Marine LakeRiver Clwyd28.7unnamed lake on Rûg estateRiver Dee8.4

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlyn HelygRiver Clwyd37Padeswood Pool12.6anglingShotwick LakeRiver Deeamenityunnamed reservoir, Cilcain5.4unnamed reservoir, Oakenholt5.7Ysceifiog Lake13.8

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlyn yr AdarRiver Glaslyn10Llyn AnafonAfon Aber13water supplyLlyn Arenig Fach34natural lakeLlyn Arenig FawrRiver Dee84 water supply for Bala town, natural lakeLlynnau BarlwydRiver Dwyryd10 + 5 industrial water supply Llyn y BiRiver Mawddach6 Llyn BodlynAfon Ysgethin42 water supply Llyn BowyddRiver Dwyryd22industrial water supply. Llyn CaerwychRiver Dwyryd5 Llyn CauRiver Dysynni33 Llyn CelynRiver Dee815river regulation Llyn ConglogRiver Dwyryd18 Llyn Conglog MawrRiver Dwyryd8 Craiglyn Dyfi also written as Creiglyn DyfiRiver Dyfi15natural corrie lakeLlyn CroesorRiver Glaslyn5Llyn Cwm CorsiogAfon Dwyryd7industrial water supply (disused) Llyn CwellynAfon Gwyrfai215 water supply, naturalLlyn Cwm BychanAfon Artro25Llyn Cwm DulynAfon Llyfni34water supplyLlyn CwmffynnonRiver Conwy20Llyn Cwm mynachRiver Mawddach14Llyn CwmorthinRiver Dwyryd22Llynnau Cwm SilynAfon Llyfni15 + 15Llyn Cwm y FoelRiver Glaslyn8Llyn CwmystradllynRiver Dwyfor98natural lakeLlyn CynwchRiver Mawddach26amenityLlyn DinasRiver Glaslyn60natural lakeLlynnau DiwauneddRiver Conwy19 + 13natural lakesLlyn DulynAfon Ysgethin5natural lake, reservoirLlyn Du'r ArdduRiver Seiont5natural lakeLlyn DwythwchRiver Seiont24Llyn y DywarchenAfon Gwyrfai40Llyn EdnoRiver Glaslyn10Llyn Eiddew mawrAfon Artro22Llyn Ffynnon y GwasAfon Gwyrfai10Llyn y GadairAfon Gwyrfai50Llyn GwynantRiver Glaslyn85Llyn HesgynRiver Dee5Llyn Hywel13Llyn IdwalRiver Ogwen28Llyn IrddynAfon Ysgethinnatural lakeLlyn LlagiRiver Glaslyn8Llyn LlydawRiver Glaslyn110Llyn LlywelynRiver Glaslyn6Llyn MairRiver Dwyryd14 Artificial lakeLlyn ManodRiver Dwyryd16Marchlyn Bach reservoirRiver Seiont Marchlyn MawrRiver SeionthydroelectricityLlyn Mwyngil (Talyllyn Lake)River Dysynni220Llyn Nantlle UchafAfon Llyfni80Llyn NewyddRiver Dwyryd12Llyn PerisRiver Seiont95lower reservoir for pump storage hydro electricityLlyn PadarnRiver Seiont280 natural lake used for recreationTanygrisiau ReservoirRiver Dwyryd95Llyn Tecwyn Isaf7Llyn Tecwyn UchafRiver Dwyryd31Bala Lake (Llyn Tegid)River Dee1,196 Largest natural water in WalesLlyn TeyrnRiver Glaslyn5Llyn TrawsfynyddRiver Dwyryd1,180 nuclear power (formerly) and hydroelectric energyLlyn TrywerynRiver Dee20Llyn WylfaAfon Mawddach6natural lake

Lake nameCatchmentGrid ref. Area (acres)Status/UseCyfarthfa Castle LakeRiver TaffamenityDol y gaer (or Pentwyn) Reservoir *River Taffwater supplyLlwyn on Reservoir *River Taffwater supplyPenywern Middle PondRiver Taffangling Penywern Top PondRiver Taffangling Pontsticill Reservoir *River Taffwater supply

Lake nameCatchmentGrid ref. Area (acres)Status/UseLlandegfedd ReservoirRiver Usk434water supplyPwll Pen ffordd goch / Keepers PondRiver Uskamenity, formerly served Garn ddyrys ironworksWentwood ReservoirRiver Usk41water supply

Lake nameCatchmentGrid ref. Area (acres)Status/UseCwmwernderi ReservoirreservoirEglwys NunyddRiver Afan260industrial water supply, fishingFurzemill PondRiver Afan5former millpond?Llyn FachRiver NeathNatural lakeRheola PondRiver Neathlarger un named lake at AberclwydRiver Neathamenitysmaller un named lake at AberclwydRiver Neathamenity

Lake nameCatchmentGrid ref. Area (acres)Status/UseBosherston LakesCoastal streamartificialLlys y Frân ReservoirWestern Cleddau212water supplyRosebush ReservoirWestern Cleddau30water supply

Lake nameCatchmentGrid ref. Area (acres)Status/UseAbernant LakeRiver Irfon5Created in 1903 by damming an oxbow of the IrfonBeacons ReservoirRiver Taff52water supplycyRiver Dyfi NaturalCaban coch ReservoirRiver Severn500See notewater supplyCantref Reservoir *River Taff42water supplyLlyn CarwRiver Wyetiny natural lakeClaerwen ReservoirRiver Severn664water supplyLlyn ClywedogRiver Severnriver regulationCraig goch ReservoirRiver Severn217water supplyCray ReservoirRiver Usk100water supplyLlyn Cwm LlwchRiver Usk1 2tiny glacier lakeDol y gaer (or Pentwyn) Reservoir *River Taffwater supplyGarreg ddu ReservoirRiver Severn500See notewater supplyLlyn GlanmerinRiver Dyfinatural lakelt=GlaslynRiver DyfiLlyn GludyRiver UskLlan Bwch llyn LakeRiver Wye c.30 Mesotrophic lakeLlangorse LakeRiver Usk327natural lake, largest in South WalesLlangynidr ReservoirEbbw RiverreservoirLlyn LluncawsAfon Tanatnatural lakeLlyn y Fan FawrRiver TaweUpper Neuadd ReservoirRiver Taffwater supplyPenygarreg ReservoirRiver Severn124water supplyPontsticill Reservoir*River Taffwater supplyPwll gwy rhocRiver Clydachc.5natural lakeTalybont ReservoirRiver Uskwater supplyTy Mawr PoolRiver Usknatural lakeLake Vyrnwy River Vyrnwywater supplyYstradfellte ReservoirRiver Neathwater 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.

Lake nameCatchmentGrid ref. Area (acres)Status/UseCantref Reservoir *River Taffwater supplyDare Valley Country Park lower lakeRiver CynonamenityLluest wen ReservoirRiver Rhondda FachLlwyn on Reservoir *River Taff150water supplyLlyn FawrRiver Cynon24 Natural but expanded for water supplyNant hir ReservoirRiver CynonNant moel ReservoirRiver CynonPenderyn ReservoirRiver Neath?Perthgelyn ReservoirRiver Cynonreservoir

Lake nameCatchmentGrid ref. Area (acres)Status/UseLake FendrodRiver Tawe13amenityLower Lliw ReservoirRiver Lliwwater supplyOxwich Marsh Lakecoastal stream>15natural lakeUpper Lliw ReservoirRiver Lliwwater supplyTawe BarrageRiver TaweamenitySpecimen LakeRiver Loughor10amenity/angling

Lake nameCatchmentGrid ref. Area (acres)Status/UseBlaen Bran Reservoir (lower)Afon LwydCoity PondAfon Lwydformer reservoir

Lake nameCatchmentGrid ref. Area (acres)Status/UseCosmeston LakeRiver CadoxtonamenityHensol LakeRiver Elyamenity and reservoirHensol Mill PondRiver Ely6former mill pond

Lake nameCatchmentGrid ref. Area (acres)Status/UseCae Llwyd ReservoirRiver Dee10.6Chirk Castle LakeRiver Dee11.1Fenn's Bank Mere8.4Gresford FlashRiver Dee8.2amenityHanmer Mere44.4natural lake, SSSIMonk's PoolRiver Dee5.2Pant yr ochain LakeRiver Dee14.1Penycae Top ReservoirRiver Dee6.2Ty Mawr ReservoirRiver Dee21.3Wynnstay Park LakeRiver Dee8.9

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

Lake nameCatchmentGrid ref. Area (acres)Status/UseCounty / County Borough(s)Beacons ReservoirRiver Taff52water supplyPowysCantref Reservoir *River Taff42water supplyPowys, Rhondda Cynon TafCray ReservoirRiver Usk100water supplyPowysDol y gaer (or Pentwyn) Reservoir *River Taffwater supplyPowysLlyn GludyRiver UskPowysLlangorse LakeRiver Wye327natural lakePowysLlangynidr ReservoirEbbw RiverreservoirPowysLlwyn on Reservoir *River Taff150water supplyMerthyr Tydfil, Rhondda Cynon TafLlyn y Fan FawrRiver Tawenatural lakePowysUpper Neuadd ReservoirRiver Taffwater supplyPowysPontsticill Reservoir*River Taffwater supplyMerthyr Tydfil, Powys Pwll Gwy rhocRiver Clydachc.5natural lakePowysTalybont ReservoirRiver Uskwater supplyPowysTy Mawr PoolRiver Usknatural lakePowysUsk ReservoirRiver Uskwater supplyCarmarthenshire, PowysYstradfellte ReservoirRiver Neathwater supplyPowys

Lake nameCatchmentGrid ref. Area (acres)Status/UsePrincipal area/sBosherston LakesCoastal streamnatural lakesPembrokeshireRosebush Reservoir, RosebushWestern Cleddau30water supplyPembrokeshire

Lake nameCatchmentGrid ref. Area (acres)Status/UsePrincipal area/sLlyn yr AdarRiver Glaslyn10GwyneddLlyn AnafonAfon Aber13water supplyLlyn Arenig Fach34natural lakeGwyneddLlyn Arenig FawrRiver Dee84 water supply, natural lakeGwyneddLlynnau BarlwydRiver Dwyryd10 + 5 industrial water supply GwyneddLlyn y BiRiver Mawddach6 GwyneddLlyn BochlwydRiver Ogwen10ConwyLlyn Bodgynydd14industrial supply (disused)ConwyLlyn BodlynAfon Ysgethin42 water supply GwyneddLlyn BowyddRiver Dwyryd22industrial water supplyGwyneddLlyn CaerwychRiver Dwyryd5 GwyneddLlyn CauRiver Dysynni33 GwyneddLlyn CelynRiver Dee815river regulation GwyneddLlyn CoedtyRiver Conwy11.6 hydroelectricityConwyLlyn ConglogRiver Dwyryd18 GwyneddLlyn Conglog MawrRiver Dwyryd8 GwyneddLlyn ConwyRiver Conwy101.3water supply for LlanrwstConwyLlyn CowlydRiver Conwy269 water supply for ConwyConwyLlyn CrafnantRiver Conwy52former water supplyConwyCreiglyn DyfiRiver Dyfi15natural corrie lakeGwyneddLlyn CroesorRiver Glaslyn5GwyneddLlyn Cwm Corsiog7industrial water supply (disused) Llyn CwellynAfon Gwyrfai215 water supply GwyneddLlyn Cwm BychanAfon Artro25GwyneddLlyn Cwm DulynAfon Llyfni34water supplyGwyneddLlyn CwmffynnonRiver Conwy20GwyneddLlyn Cwm mynachRiver Mawddach14GwyneddLlyn CwmorthinRiver Dwyryd22GwyneddLlynnau Cwm SilynAfon Llyfni15 + 15GwyneddLlyn Cwm y FoelRiver Glaslyn8GwyneddLlyn CwmystradllynRiver Dwyfor98natural lakeGwyneddLlyn CynwchRiver Mawddach26amenityGwyneddLlyn DinasRiver Glaslyn60natural lakeGwyneddLlynnau DiwauneddRiver Conwy19 + 13natural lakesGwyneddLlyn DulynAfon Ysgethin5natural lake, reservoirGwyneddDulyn ReservoirRiver Conwy33water supplyConwyLlyn Du'r ArdduRiver Seiont5natural lakeGwyneddLlyn DwythwchRiver Seiont24GwyneddLlyn y DywarchenAfon Gwyrfai40GwyneddLlyn EdnoRiver Glaslyn10GwyneddLlyn Eiddew mawrAfon Artro22GwyneddLlyn EigiauRiver Conwy120ConwyLlyn ElsiRiver Conwy26water supplyConwyLlyn Ffynnon y GwasAfon Gwyrfai10GwyneddLlyn y foelAfon Lledrnatural lakeConwyLlyn y GadairAfon Gwyrfai50GwyneddLlyn GeirionyddRiver Conwy45ConwyLlyn GoddionduonRiver Conwy10ConwyLlyn GwynantRiver Glaslyn85GwyneddLlyn HesgynRiver Dee5GwyneddLlyn Hywel13GwyneddLlyn IdwalRiver Ogwen28GwyneddLlyn IrddynAfon Ysgethinnatural lakeGwyneddLlyn LlagiRiver Glaslyn8GwyneddFfynnon LloerRiver Ogwen6ConwyFfynnon LlugwyRiver Conwy40ConwyLlyn LlydawRiver Glaslyn110GwyneddLlyn LlywelynRiver Glaslyn6GwyneddLlyn MairRiver Dwyryd14GwyneddMarchlyn Bach reservoirRiver Seiont GwyneddMarchlyn MawrRiver SeionthydroelectricityGwyneddTal y llyn Lake (Llyn Mwyngil)River Dysynni220GwyneddLlynnau MymbyrRiver Conwy58ConwyLlyn Nantlle UchafAfon Llyfni80GwyneddLlyn NewyddRiver Dwyryd12GwyneddLlyn OgwenRiver Ogwen78ConwyLlyn y ParcRiver Conwy22ConwyTanygrisiau ReservoirRiver Dwyryd95GwyneddLlyn Tecwyn Isaf7GwyneddLlyn Tecwyn UchafRiver Dwyryd31GwyneddBala Lake – (Llyn Tegid)River Dee1,196GwyneddLlyn TeyrnRiver Glaslyn5GwyneddLlyn TrawsfynyddRiver Dwyryd1,180 nuclear power (formerly) & HEPGwyneddLlyn TrywerynRiver Dee20GwyneddLlyn Wylfa6Gwynedd

Lake nameCatchmentGrid ref. Area (acres)Status/UsePrincipal areaBryn bach PondSirhowy Riverformerly industrial use (not same site as modern lake)Blaenau GwentCairn Mound Impounding ReservoirRiver Clydachformer reservoirBlaenau GwentClyn mil PondRiver Taffformerly industrial useMerthyr TydfilGlyn dyrys PondRiver Taffformerly industrial useMerthyr TydfilHirwaun PondsRiver Cynonformerly industrial useRhondda Cynon TafLower Neuadd ReservoirRiver Taffformer reservoir (dam breached)Merthyr TydfilLlyn Nantlle isafAfon Llyfninatural lakeGwyneddPitwellt PondRiver Taffformer reservoir (dam breached)Merthyr TydfilRhyd y blew Pond (Rassa)Ebbw Riverformerly industrial useBlaenau GwentScotch Peter's ReservoirSirhowy Riverformer reservoirBlaenau Gwent