- Category: Water Feature
- Type: Inland Water
- Latitude/Longitude: 51°59'29"N 3°37'19"W
- Eastings/Northings: 288721, 233791
- OS Grid: SN887337
- Mapcode Local: GBR YC.JQ66
- Mapcode Global: VH5F6.56HQ
Location and coordinates are for the approximate centre of Llyn Nant-llys within this administrative area.
Geographic features and populated places may cross administrative borders.