- Category: Water Feature
- Type: Island
- Latitude/Longitude: 53°25'2"N 4°20'47"W
- Eastings/Northings: 244160, 393746
- OS Grid: SH441937
- Mapcode Local: GBR HMMN.ZRG
- Mapcode Global: WH421.6CJH
Location and coordinates are for the approximate centre of Graig-ddu within this administrative area.
Geographic features and populated places may cross administrative borders.