- Category: Geographic Feature
- Type: Valley
- Latitude/Longitude: 53°5'8"N 4°3'52"W
- Eastings/Northings: 261815, 356266
- OS Grid: SH618562
- Mapcode Local: GBR 5S.9P3J
- Mapcode Global: WH54V.JPNS
Location and coordinates are for the approximate centre of Cwm Glas Mawr within this administrative area.
Geographic features and populated places may cross administrative borders.