- Category: Water Feature
- Type: Island
- Latitude/Longitude: 54°13'29"N 0°17'30"W
- Eastings/Northings: 511465, 482352
- OS Grid: TA114823
- Mapcode Local: GBR VMDL.M9
- Mapcode Global: WHHDL.H28J
Location and coordinates are for the approximate centre of Under Nine Rocks within this administrative area.
Geographic features and populated places may cross administrative borders.