The German philologist Friedrich Althaus (1829-1897) wrote in 1889: "Cader Idris is to Barmouth what the Vesuvius is to Naples. (...) The prospect from the summit is said to be the grandest in all of Wales. (...) Climbing Cader Idris therefore takes top priority among many visitors of Barmouth."

William Wordsworth, a visitor to Barmouth in the 19th century, described it thus: "With a fine sea view in front, the mountains behind, the glorious estuary running 8 mi inland, and Cadair Idris within