- Category: Water Feature
- Type: Island
- Latitude/Longitude: 51°46'19"N 0°53'58"E
- Eastings/Northings: 600149, 212121
- OS Grid: TM001121
- Mapcode Local: GBR SPJ.S9H
- Mapcode Global: VHKGK.JQXG
Location and coordinates are for the approximate centre of Cobmarsh Island within this administrative area.
Geographic features and populated places may cross administrative borders.