- Category: Water Feature
- Type: Other Water Feature
- Latitude/Longitude: 52°55'24"N 4°11'43"W
- Eastings/Northings: 252500, 338500
- OS Grid: SH525385
- Mapcode Local: GBR 5M.MTK7
- Mapcode Global: WH55K.JSC2
Location and coordinates are for the approximate centre of Llyn Ystumllyn within this administrative area.
Geographic features and populated places may cross administrative borders.