- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°16'56"N 4°2'41"W
- Eastings/Northings: 260614, 266892
- OS Grid: SN606668
- Mapcode Local: GBR 8T.Y8RS
- Mapcode Global: VH4FY.VW2M
Location and coordinates are for the approximate centre of Llyn Eiddwen within this administrative area.
Geographic features and populated places may cross administrative borders.