- Category: Water Feature
- Type: Island
- Latitude/Longitude: 55°9'48"N 1°33'21"W
- Eastings/Northings: 428384, 585550
- OS Grid: NZ283855
- Mapcode Local: GBR K8KQ.XV
- Mapcode Global: WHC2T.2G9Y
Location and coordinates are for the approximate centre of Castle Island within this administrative area.
Geographic features and populated places may cross administrative borders.