- Category: Water Feature
- Type: Island
- Latitude/Longitude: 53°18'59"N 4°37'41"W
- Eastings/Northings: 225033, 383166
- OS Grid: SH250831
- Mapcode Local: GBR GMYY.2TP
- Mapcode Global: WH314.WWBY
Location and coordinates are for the approximate centre of Graig Ddu within this administrative area.
Geographic features and populated places may cross administrative borders.