List of lakes of Wales

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.

By area

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

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, which is also the second largest natural lake.

By counties and county boroughs

This list of Welsh lakes ordered by principal areas includes lakes with a surface area of greater than, but excludes those lakes and ponds created as part of an active industrial site 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.

Conwy

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.

By national park

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

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: