- Category: Water Feature
- Type: Island
- Latitude/Longitude: 53°13'21"N 4°10'16"W
- Eastings/Northings: 255136, 371721
- OS Grid: SH551717
- Mapcode Local: GBR 5N.0TDR
- Mapcode Global: WH546.W8T7
Location and coordinates are for the approximate centre of Ynys Tysilio within this administrative area.
Geographic features and populated places may cross administrative borders.