- Category: Water Feature
- Type: Island
- Latitude/Longitude: 49°57'53"N 6°17'42"W
- Eastings/Northings: 92088, 16040
- OS Grid: SV920160
- Mapcode Local: GBR BXVS.19G
- Mapcode Global: VGYBY.T4TR
Location and coordinates are for the approximate centre of St Martin's within this administrative area.
Geographic features and populated places may cross administrative borders.