- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°46'46"N 4°1'58"W
- Eastings/Northings: 262985, 322166
- OS Grid: SH629221
- Mapcode Local: GBR 5T.XYNB
- Mapcode Global: WH56F.0DWF
Location and coordinates are for the approximate centre of Llyn Irddyn within this administrative area.
Geographic features and populated places may cross administrative borders.