|Elidir Fawr (3000ft+) lies N of Snowdon in the Snowdonia National Park (Wales) and ENE of the town of Llanberis, from where its broad grassy SW slopes appear extensively scarred by former slate quarrying. It can be approached from the south by a relatively dull track following the Afon Dudodyn valley from Nant Peris, or from Dinorwig via the service road to the Marchlyn Mawr reservoir thence up its steep N slopes.
The best walking approach, although more distant, is from the East. An E ridge (with crags to N) runs down to Bwlch y Marchlyn, then continues NE to rounded Mynydd Perfedd (812m). Mynydd Perfedd links SE via Bwlch y Brecan to Foel Goch (831m) which in turn links S across a col at about 755m to Y Garn (qv). A convenient track from this latter col contours the W slopes of Foel Goch and the S slopes of Mynydd Perfedd to reach Bwlch y Marchlyn, enabling Elidir Fawr and Y Garn (3000ft+) to be climbed together with minimal extra ascent.