- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 51°47'46"N 3°26'22"W
- Eastings/Northings: 300827, 211825
- OS Grid: SO008118
- Mapcode Local: GBR YM.Y1GD
- Mapcode Global: VH6CQ.B3JS
Location and coordinates are for the approximate centre of Llwyn-on Reservoir within this administrative area.
Geographic features and populated places may cross administrative borders.