- Category: Water Feature
- Type: Island
- Latitude/Longitude: 57°40'16"N 2°24'29"W
- Eastings/Northings: 375750, 864676
- OS Grid: NJ757646
- Mapcode Local: GBR N8DF.ZDV
- Mapcode Global: WH8LX.ZFDY
Location and coordinates are for the approximate centre of Grey Mare within this administrative area.
Geographic features and populated places may cross administrative borders.