- Category: Geographic Feature
- Type: Valley
- Latitude/Longitude: 52°16'28"N 3°13'23"W
- Eastings/Northings: 316636, 264745
- OS Grid: SO166647
- Mapcode Local: GBR 9X.YT9C
- Mapcode Global: VH69J.23V6
Location and coordinates are for the approximate centre of Cwm Merwys within this administrative area.
Geographic features and populated places may cross administrative borders.