Cwm Silyn is a remote upland llyn in a glacial cwm beneath the Nantlle Ridge crags, west of Snowdon — ten hectares of wild brown trout and a relict Arctic char population. A mile's walk from Llanllyfni and you're somewhere a Welsh fly fisher would call proper mountain water. The SGLL ticket covers it; the char take a four-fish daily limit alongside the regular trout bag.
- Lake
- Ordovician volcanics

