- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°24'21"N 3°35'57"W
- Eastings/Northings: 291310, 279861
- OS Grid: SN913798
- Mapcode Local: GBR 9D.PJJ6
- Mapcode Global: VH5C2.KSMH
Location and coordinates are for the approximate centre of Llyn Tan-y-llwyn within this administrative area.
Geographic features and populated places may cross administrative borders.