- Category: Geographic Feature
- Type: Valley
- Latitude/Longitude: 53°2'3"N 4°13'7"W
- Eastings/Northings: 251323, 350854
- OS Grid: SH513508
- Mapcode Local: GBR 5L.DTZ6
- Mapcode Global: WH54Z.5ZBQ
Location and coordinates are for the approximate centre of Cwm Silyn within this administrative area.
Geographic features and populated places may cross administrative borders.