- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 52°47'45"N 3°57'39"W
- Eastings/Northings: 267883, 323858
- OS Grid: SH678238
- Mapcode Local: GBR 5X.WY0R
- Mapcode Global: WH568.4Z3B
Location and coordinates are for the approximate centre of Llyn Cwm-mynach within this administrative area.
Geographic features and populated places may cross administrative borders.