- Category: Geographic Feature
- Type: Cirque or Hollow
- Latitude/Longitude: 53°8'5"N 4°4'16"W
- Eastings/Northings: 261532, 361756
- OS Grid: SH615617
- Mapcode Local: GBR 5S.6FJ2
- Mapcode Global: WH54N.FGJK
Location and coordinates are for the approximate centre of Cwm Marchlyn within this administrative area.
Geographic features and populated places may cross administrative borders.