- Category: Water Feature
- Type: Island
- Latitude/Longitude: 52°1'41"N 5°4'43"W
- Eastings/Northings: 188884, 241108
- OS Grid: SM888411
- Mapcode Local: GBR CF.GGWF
- Mapcode Global: VH1QC.X9C3
Location and coordinates are for the approximate centre of Carreg Onnen within this administrative area.
Geographic features and populated places may cross administrative borders.