- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°57'8"N 4°1'4"W
- Eastings/Northings: 264528, 341342
- OS Grid: SH645413
- Mapcode Local: GBR 5V.L2GH
- Mapcode Global: WH55N.72Y0
Location and coordinates are for the approximate centre of Llyn Hafon-y-llyn within this administrative area.
Geographic features and populated places may cross administrative borders.