- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°58'46"N 3°58'3"W
- Eastings/Northings: 267997, 344271
- OS Grid: SH679442
- Mapcode Local: GBR 5X.J8PL
- Mapcode Global: WH55H.0CZP
Location and coordinates are for the approximate centre of Tanygrisiau Reservoir within this administrative area.
Geographic features and populated places may cross administrative borders.