- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°31'13"N 3°44'34"W
- Eastings/Northings: 281845, 292824
- OS Grid: SN818928
- Mapcode Local: GBR 96.GC3X
- Mapcode Global: VH5BF.2XN5
Location and coordinates are for the approximate centre of Llyn Cwm-byr within this administrative area.
Geographic features and populated places may cross administrative borders.