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The Gwynedd Council's guide to Plas Glynllifon states of the amphitheatre:
(It) is an open-air theatre made of local slate and stone and has been the venue for concerts during the warm summer months. It has drama as its main theme and celebrates the work of Welsh playwrights. There are two viewing towers, one dedicated to Saunders Lewis and the other to John Gwilym Jones, a local playwright who wrote of the estate in the Newborough period. The stage is located on the far side of the river on Yew Tree Island. The island was man-made during the Newboroughs’ time. It is boat-shaped with Irish Yew trees planted to form arches during the 1820’s.

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