- Category: Water Feature
- Type: Island
- Latitude/Longitude: 51°58'57"N 5°5'11"W
- Eastings/Northings: 188143, 236087
- OS Grid: SM881360
- Mapcode Local: GBR CF.K6YY
- Mapcode Global: VH1QK.SFBD
Location and coordinates are for the approximate centre of Carreg Herefio within this administrative area.
Geographic features and populated places may cross administrative borders.