- Category: Water Feature
- Type: Island
- Latitude/Longitude: 52°1'42"N 5°4'37"W
- Eastings/Northings: 189002, 241148
- OS Grid: SM890411
- Mapcode Local: GBR CF.G9BV
- Mapcode Global: VH1QC.Y88S
Location and coordinates are for the approximate centre of Ynys Onnen within this administrative area.
Geographic features and populated places may cross administrative borders.