Cilgwyn quarry

Cilgwyn is a slate quarry in Nantlle Valley with three main extraction pits connected by an extensive tramway network. The pits at Gloddfa Glitiau, Old Cilgwyn, and Veingoch were worked to extract stone for roofing and building purposes.

The quarry began operations during the medieval period and supplied slate for important buildings throughout Wales. Ownership changed hands multiple times over the centuries, with financial difficulties recurring throughout its working life.

The quarry archive at the University of Wales Bangor contains business papers, accounts, correspondence, and accident records from 1879 to 1933.

The site is largely abandoned and requires caution when exploring the old pits and structures. Visitors should wear sturdy footwear and be especially careful during wet or slippery conditions.

Slate from this quarry was so highly regarded that it was used for royal buildings during medieval military campaigns. This royal association helped establish the site's reputation across generations of workers and buyers.

Location: Gwynedd

GPS coordinates: 53.06150,-4.23872

Latest update: December 14, 2025 11:43