The Dinorwic Slate Quarry is a large former slate quarry, now home to the Welsh National Slate Museum, located between the villages of Llanberis and Dinorwig in north Wales. It was the second largest slate quarry in Wales, indeed in the world, after the neighbouring Penrhyn Quarry. It covered more than 700 acres (2.8 km²) consisting of two main quarry sections with 20 galleries in each and a number of ancillary workings.