- Category: Geographic Feature
- Type: Valley
- Latitude/Longitude: 52°16'1"N 3°10'52"W
- Eastings/Northings: 319482, 263886
- OS Grid: SO194638
- Mapcode Local: GBR 9Y.ZCFQ
- Mapcode Global: VH69J.T80T
Location and coordinates are for the approximate centre of Cwm Sian within this administrative area.
Geographic features and populated places may cross administrative borders.