List of lakes of Wales

In terms of surface area, the ten largest lakes in Wales are • Llyn Tegid (Bala Lake) — • Llyn Trawsfynydd — • Lake Vyrnwy — • Llyn Brenig — • Llyn Celyn — • Llyn Alaw — • Claerwen Reservoir — • Clywedog Reservoir — • Nant-y-moch Reservoir — • Caban Coch Reservoir — All of the above, with the exception of Llyn Tegid, are reservoirs held back by dams. Llyn Tegid was the largest natural lake in Wales though its level has been artificially controlled by sluices since about 1804. 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 , 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 (*). Anglesey Blaenau Gwent Bridgend Caerphilly Cardiff Carmarthenshire Ceredigion Conwy Denbighshire Flintshire Gwynedd Merthyr Tydfil Monmouthshire Neath Port Talbot Pembrokeshire Powys 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 Swansea Torfaen Vale of Glamorgan Wrexham ==By national park==

Lakes and reservoirs within each of Wales' three national parks. Brecon Beacons Pembrokeshire Coast Snowdonia ==By supply to England==

Many Welsh lakes supply the nation itself with water, however, some lakes and reservoirs supply England. The main reservoirs created for this purpose include: ==Former lakes==