- Category: Geographic Feature
- Type: Valley
- Latitude/Longitude: 52°23'6"N 3°58'7"W
- Eastings/Northings: 266108, 278169
- OS Grid: SN661781
- Mapcode Local: GBR 8X.QX1Q
- Mapcode Global: VH4FM.597X
Location and coordinates are for the approximate centre of Cwm Seiri within this administrative area.
Geographic features and populated places may cross administrative borders.