Rhiwbach quarry (also known as Rhiw-bach quarry) was a slate quarry located to the east of Blaenau Ffestiniog in North Wales. The quarry was a remote site; it was nearly 4 miles (6.4 km) to north-east of Duffws, the Festiniog Railway's terminus in Blaenau Ffestiniog. It was the connected to the Ffestiniog Railway by the Rhiwbach Tramway. Commercial operation began around 1812, and it finally closed in 1952. It was the last Welsh slate quarry where workers lived in barracks on the site. 'Rhiwbach' is Welsh for 'Little Hill'.